Spring is one of the four temperate seasons, following winter and preceding summer. There are various technical definitions of spring, but local usage of the term varies according to local climate and customs; when it is spring in the Northern Hemisphere, it is autumn in the Southern Hemisphere and vice versa. At the spring equinox and nights are twelve hours long, with day length increasing and night length decreasing as the season progresses. Spring and "springtime" refer to the season, to ideas of rebirth, renewal and regrowth. Subtropical and tropical areas have climates better described in terms of other seasons, e.g. dry or wet, monsoonal or cyclonic. Cultures may have local names for seasons which have little equivalence to the terms originating in Europe. Meteorologists define four seasons in many climatic areas: spring, summer and winter; these are demarcated by the values of their average temperatures on a monthly basis, with each season lasting three months. The three warmest months are by definition summer, the three coldest months are winter and the intervening gaps are spring and autumn.
Spring, when defined in this manner, can start on different dates in different regions. Thus, in the US and UK, spring months are March and May, while in New Zealand and Australia, spring conventionally begins on September 1 and ends November 30. Swedish meteorologists define the beginning of spring as the first occasion on which the average daytime temperature exceeds zero degrees Celsius for seven consecutive days, thus the date varies with latitude and elevation. In some cultures in the Northern Hemisphere, the astronomical vernal equinox is taken to mark the first day of spring, the summer solstice is taken as the first day of summer. In Persian culture the first day of spring is the first day of the first month which begins on 20 or 21 March. In other traditions, the equinox is taken as mid-spring. In the traditional Chinese calendar, the "spring" season consists of the days between Lichun, taking Chunfen as its midpoint ending at Lixia. According to the Celtic tradition, based on daylight and the strength of the noon sun, spring begins in early February and continues until early May.
The beginning of spring is not always determined by fixed calendar dates. The phenological or ecological definition of spring relates to biological indicators, such as the blossoming of a range of plant species, the activities of animals, the special smell of soil that has reached the temperature for micro flora to flourish; these indicators, along with the beginning of spring, vary according to the local climate and according to the specific weather of a particular year. Most ecologists divide the year into six seasons. In addition to spring, ecological reckoning identifies an earlier separate prevernal season between the hibernal and vernal seasons; this is a time when only the hardiest flowers like the crocus are in bloom, sometimes while there is still some snowcover on the ground. During early spring, the axis of the Earth is increasing its tilt relative to the Sun, the length of daylight increases for the relevant hemisphere; the hemisphere begins to warm causing new plant growth to "spring forth," giving the season its name.
Any snow begins to melt, swelling streams with runoff and any frosts become less severe. In climates that have no snow, rare frosts and ground temperatures increase more rapidly. Many flowering plants bloom at this time of year, in a long succession, sometimes beginning when snow is still on the ground and continuing into early summer. In snowless areas, "spring" may begin as early as February or August, heralded by the blooming of deciduous magnolias and quince. Many temperate areas have a dry spring, wet autumn, which brings about flowering in this season, more consistent with the need for water, as well as warmth. Subarctic areas may not experience "spring" at all until May. While spring is a result of the warmth caused by the changing orientation of the Earth's axis relative to the Sun, the weather in many parts of the world is affected by other, less predictable events; the rainfall in spring follows trends more related to longer cycles—such as the solar cycle—or events created by ocean currents and ocean temperatures—for example, the El Niño effect and the Southern Oscillation Index.
Unstable spring weather may occur more when warm air begins to invade from lower latitudes, while cold air is still pushing from the Polar regions. Flooding is most common in and near mountainous areas during this time of year, because of snow-melt, accelerated by warm rains. In North America, Tornado Alley is most active at this time of year since the Rocky Mountains prevent the surging hot and cold air masses from spreading eastward, instead force them into direct conflict. Besides tornadoes, supercell thunderstorms can produce dangerously large hail and high winds, for which a severe thunderstorm warning or tornado warning is issued. More so than in winter, the jet streams play an important role in unstable and severe Northern Hemisphere weather in springtime. In recent decades, season creep has been observed, which means that many phenological signs of spring are occurring earlier in many regions by around two days per decade. Spring in the Southern Hemisphere is different in several significant ways to that of the Northern Hemisphere
Sir John Frederick William Herschel, 1st Baronet was an English polymath, astronomer, inventor, experimental photographer who invented the blueprint, did botanical work. Herschel originated the use of the Julian day system in astronomy, he named four moons of Uranus. He made many contributions to the science of photography, investigated colour blindness and the chemical power of ultraviolet rays. Herschel was born in Slough, the son of Mary Baldwin and William Herschel, he was the nephew of astronomer Caroline Herschel. He studied shortly at Eton College and St John's College, graduating as Senior Wrangler in 1813, it was during his time as an undergraduate that he became friends with the mathematicians Charles Babbage and George Peacock. He started working with his father, he took up astronomy in 1816, building a reflecting telescope with a mirror 18 inches in diameter, with a 20-foot focal length. Between 1821 and 1823 he re-examined, with the double stars catalogued by his father, he was one of the founders of the Royal Astronomical Society in 1820.
For his work with his father, he was presented with the Gold Medal of the Royal Astronomical Society in 1826, with the Lalande Medal of the French Academy of Sciences in 1825, while in 1821 the Royal Society bestowed upon him the Copley Medal for his mathematical contributions to their Transactions. Herschel was made a Knight of the Royal Guelphic Order in 1831. Herschel served as President of the Royal Astronomical Society three times: 1827–29, 1839–41 and 1847–49. Herschel's A preliminary discourse on the study of natural philosophy, published early in 1831 as part of Dionysius Lardner's Cabinet cyclopædia, set out methods of scientific investigation with an orderly relationship between observation and theorising, he described nature as being governed by laws which were difficult to discern or to state mathematically, the highest aim of natural philosophy was understanding these laws through inductive reasoning, finding a single unifying explanation for a phenomenon. This became an authoritative statement with wide influence on science at the University of Cambridge where it inspired the student Charles Darwin with "a burning zeal" to contribute to this work.
Herschel published a catalogue of his astronomical observations in 1864, as the General Catalogue of Nebulae and Clusters, a compilation of his own work and that of his father's, expanding on the senior Herschel's Catalogue of Nebulae. A further complementary volume was published posthumously, as the General Catalogue of 10,300 Multiple and Double Stars. Herschel considered astigmatism to be due to irregularity of the cornea and theorised that vision could be improved by the application of some animal jelly contained in a capsule of glass against the cornea, his views were published in an article entitled Light in 1828 and the Encyclopædia Metropolitana in 1845. Discoveries of Herschel include the galaxies NGC 7, NGC 10, NGC 25, NGC 28 Declining an offer from the Duke of Sussex that they travel to South Africa on a Navy ship and his wife paid £500 for passage on the S. S. Mountstuart Elphinstone, which departed from Portsmouth on 13 November 1833; the voyage to South Africa was made in order to catalogue the stars and other objects of the southern skies.
This was to be a completion as well as extension of the survey of the northern heavens undertaken by his father William Herschel. He arrived in Cape Town on 15 January 1834 and set up a private 21 ft telescope at Feldhausen at Claremont, a suburb of Cape Town. Amongst his other observations during this time was that of the return of Comet Halley. Herschel collaborated with Thomas Maclear, the Astronomer Royal at the Cape of Good Hope and the members of the two families became close friends. During this time, he witnessed the Great Eruption of Eta Carinae. In addition to his astronomical work, this voyage to a far corner of the British empire gave Herschel an escape from the pressures under which he found himself in London, where he was one of the most sought-after of all British men of science. While in southern Africa, he engaged in a broad variety of scientific pursuits free from a sense of strong obligations to a larger scientific community, it was, he recalled the happiest time in his life.
In an extraordinary departure from astronomy, Herschel combined his talents with those of his wife and between 1834 and 1838 they produced 131 botanical illustrations of fine quality, showing the Cape flora. Herschel used a camera lucida to obtain accurate outlines of the specimens and left the details to his wife. Though their portfolio had been intended as a personal record, despite the lack of floral dissections in the paintings, their accurate rendition makes them more valuable than many contemporary collections; some 112 of the 132 known flower studies were collected and published as Flora Herscheliana in 1996. As their home during their stay in the Cape, the Herschels had selected'Feldhausen', an old estate on the south-eastern side of Table Mountain. Here John set up his reflector to begin his survey of the southern skies. Herschel, at the same time, read widely. Intrigued by the ideas of gradual formation of landscapes set out in Charles Lyell's Principles of Geology, he wrote to Lyell on 20 February 1836 praising the book as a work that would bring "a complete revolution in subject, by alterin
Calendar reform or calendrical reform, is any significant revision of a calendar system. The term sometimes is used instead for a proposal to switch to a different calendar design; the prime objective of a calendar is to unambiguously identify any day throughout history by a specific date. Periods that contain multiple days, like weeks and years, are secondary features of a calendar for convenience. Most cultures adopt a primary dating system, but different cultures have always needed to align multiple calendars with each other, because they coexisted in the same space or had established trading relations. Once specified, a calendar design cannot be altered without becoming a new one, but if a design is sufficiently close to the one used before in the local calendar system, switching to it and hence a calendar reform is possible without disruption; some design changes, will yield date identifiers different from the previous design for some days in the distant past or future. The calendar system must clarify whether dates are changed to the new design retroactively or whether the design in use and there shall be respected.
Calendar schisms happen if not all cultures that adopted a common calendar system before perform a calendar reform at the same time. If date identifiers are similar but different and mistakes are unavoidable. Most calendars have several rules which could be altered by reform: Whether and how days are grouped into subdivisions such as months and weeks, days outside those subdivisions, if any. Which years are common years and how they differ. Numbering of years, selection of the epoch, the issue of year zero. Start of the year. If a week is retained, the start and names of its days. Start of the day. If months are retained, number and names of months. Special days and periods. Alignment with social cycles. Alignment with astronomical cycles. Alignment with biological cycles. Literal notation of dates. Most calendar reforms have been made in order to synchronize the calendar with the astronomical year and/or the synodic month in lunar or lunisolar calendars. Most reforms for calendars have been to make them more accurate.
This has happened to various lunar and lunisolar calendars, the Julian calendar when it was altered to the Gregorian calendar. The fundamental problems of the calendar are that the astronomical year has neither a whole number of days nor a whole number of lunar months; such remainders could accumulate from one period to the next, thereby driving the cycles out of synch. A typical solution to force synchronization is'intercalation'; this means adding an extra day into the cycle. An alternative approach is to ignore the mismatch and let the cycles continue to drift apart; the general approaches include: The lunar calendar, which fits days into the cycle of lunar months, adding an extra day when needed, while ignoring the annual solar cycle of the seasons. The solar calendar, which fits artificial months into the year, adding an extra day into one month when needed, while ignoring the lunar cycle of new/full moons; the lunisolar calendar, which keeps both the lunar and solar cycles, adding an extra month into the year when needed.
An obvious disadvantage of the lunisolar method of inserting a whole extra month is the large irregularity of the length of the year from one to the next. The simplicity of a lunar calendar has always been outweighed by its inability to track the seasons, a solar calendar is used in conjunction to remedy this defect. Identifying the lunar cycle month requires straightforward observation of the Moon on a clear night. However, identifying seasonal cycles requires much more methodical observation of stars or a device to track solar day-to-day progression, such as that established at places like Stonehenge. After centuries of empirical observations, the theoretical aspects of calendar construction could become more refined, enabling predictions that identified the need for reform. There have been 50 to 100 reforms of the traditional Chinese calendar over 2500 years, most of which were intended to better fit the calendar months to astronomical lunations and to more add the extra month so that the regular months maintain their proper seasonal positions though each seasonal marker can occur anywhere within its month.
There have been at least four similar reforms of the lunisolar version of the Hindu calendar, all intended to make the month a better match to the lunation and to make the year a better fit to the sidereal year. There have been reforms of the solar version of the Hindu calendar which changed the distribution of the days in each month to better match the length of time that the Sun spends in each sidereal zodiacal sign; the same applies to the Buddhist calendar. The first millennium reform of the Hebrew calendar changed it from an observational calendar into a calculated calendar; the Islamic calendar was a reform of the preceding lunisolar calendar which divorced it from the solar year. Another reform was performed in Seljuk Persia by Omar Khayyam and others, developing the computed Jalali calendar; when Julius Caesar
Winter is the coldest season of the year in polar and temperate zones. It occurs before spring in each year. Winter is caused by the axis of the Earth. Different cultures define different dates as the start of winter, some use a definition based on weather; when it is winter in the Northern Hemisphere, it is summer in the Southern Hemisphere, vice versa. In many regions, winter is associated with freezing temperatures; the moment of winter solstice is when the Sun's elevation with respect to the North or South Pole is at its most negative value. The day on which this occurs has the shortest day and the longest night, with day length increasing and night length decreasing as the season progresses after the solstice; the earliest sunset and latest sunrise dates outside the polar regions differ from the date of the winter solstice and these depend on latitude, due to the variation in the solar day throughout the year caused by the Earth's elliptical orbit. The English word "winter" comes from the Proto-Indo-European root "wend," relating to water.
The tilt of the Earth's axis relative to its orbital plane plays a large role in the formation of weather. The Earth is tilted at an angle of 23.44° to the plane of its orbit, causing different latitudes to directly face the Sun as the Earth moves through its orbit. This variation brings about seasons; when it is winter in the Northern Hemisphere, the Southern Hemisphere faces the Sun more directly and thus experiences warmer temperatures than the Northern Hemisphere. Conversely, winter in the Southern Hemisphere occurs when the Northern Hemisphere is tilted more toward the Sun. From the perspective of an observer on the Earth, the winter Sun has a lower maximum altitude in the sky than the summer Sun. During winter in either hemisphere, the lower altitude of the Sun causes the sunlight to hit the Earth at an oblique angle, thus a lower amount of solar radiation strikes the Earth per unit of surface area. Furthermore, the light must travel a longer distance through the atmosphere, allowing the atmosphere to dissipate more heat.
Compared with these effects, the effect of the changes in the distance of the Earth from the Sun is negligible. The manifestation of the meteorological winter in the northerly snow–prone latitudes is variable depending on elevation, position versus marine winds and the amount of precipitation. For instance, within Canada, Winnipeg on the Great Plains, a long way from the ocean, has a January high of −11.3 °C and a low of −21.4 °C. In comparison, Vancouver on the west coast with a marine influence from moderating Pacific winds has a January low of 1.4 °C with days well above freezing at 6.9 °C. Both places are at 49°N latitude, in the same western half of the continent. A similar but less extreme effect is found in Europe: in spite of their northerly latitude, the British Isles have not a single non-mountain weather station with a below-freezing mean January temperature. Meteorological reckoning is the method of measuring the winter season used by meteorologists based on "sensible weather patterns" for record keeping purposes, so the start of meteorological winter varies with latitude.
Winter is defined by meteorologists to be the three calendar months with the lowest average temperatures. This corresponds to the months of December and February in the Northern Hemisphere, June and August in the Southern Hemisphere; the coldest average temperatures of the season are experienced in January or February in the Northern Hemisphere and in June, July or August in the Southern Hemisphere. Nighttime predominates in the winter season, in some regions winter has the highest rate of precipitation as well as prolonged dampness because of permanent snow cover or high precipitation rates coupled with low temperatures, precluding evaporation. Blizzards develop and cause many transportation delays. Diamond dust known as ice needles or ice crystals, forms at temperatures approaching −40 °C due to air with higher moisture from above mixing with colder, surface-based air, they are made of simple hexagonal ice crystals. The Swedish meteorological institute defines winter as when the daily mean temperatures are below 0 °C for five consecutive days.
According to the SMHI, winter in Scandinavia is more pronounced when Atlantic low-pressure systems take more southerly and northerly routes, leaving the path open for high-pressure systems to come in and cold temperatures to occur. As a result, the coldest January on record in Stockholm, in 1987, was the sunniest. Accumulations of snow and ice are associated with winter in the Northern Hemisphere, due to the large land masses there. In the Southern Hemisphere, the more maritime climate and the relative lack of land south of 40°S makes the winters milder. In this region, snow occurs every year in elevated regions such as the Andes, the Great Dividing Range in Australia, the mountains of New Zealand, occurs in the southerly Patagonia region of South Argentina. Snow occurs year-round in Antarctica. In the Northern Hemisphere, some authorities define the period of winter based on astronomical fixed points, regardless of weather conditions. In one version of this definition, winter begins at the winter solstice and ends at the ver
Summer is the hottest of the four temperate seasons, falling after spring and before autumn. At the summer solstice, the days are longest and the nights are shortest, with day length decreasing as the season progresses after the solstice; the date of the beginning of summer varies according to climate and culture. When it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere, vice versa. From an astronomical view, the equinoxes and solstices would be the middle of the respective seasons, but sometimes astronomical summer is defined as starting at the solstice, the time of maximal insolation identified with the 21st day of June or December. A variable seasonal lag means that the meteorological center of the season, based on average temperature patterns, occurs several weeks after the time of maximal insolation; the meteorological convention is to define summer as comprising the months of June and August in the northern hemisphere and the months of December and February in the southern hemisphere.
Under meteorological definitions, all seasons are arbitrarily set to start at the beginning of a calendar month and end at the end of a month. This meteorological definition of summer aligns with the viewed notion of summer as the season with the longest days of the year, in which daylight predominates; the meteorological reckoning of seasons is used in Australia, Denmark and Japan. It is used by many in the United Kingdom. In Ireland, the summer months according to the national meteorological service, Met Éireann, are June and August. However, according to the Irish Calendar, summer ends on 1 August. School textbooks in Ireland follow the cultural norm of summer commencing on 1 May rather than the meteorological definition of 1 June. Days continue to lengthen from equinox to solstice and summer days progressively shorten after the solstice, so meteorological summer encompasses the build-up to the longest day and a diminishing thereafter, with summer having many more hours of daylight than spring.
Reckoning by hours of daylight alone, summer solstice marks the midpoint, not the beginning, of the seasons. Midsummer takes place over the shortest night of the year, the summer solstice, or on a nearby date that varies with tradition. Where a seasonal lag of half a season or more is common, reckoning based on astronomical markers is shifted half a season. By this method, in North America, summer is the period from the summer solstice to the autumn equinox. Reckoning by cultural festivals, the summer season in the United States is traditionally regarded as beginning on Memorial Day weekend and ending on Labor Day, more in line with the meteorological definition for the parts of the country that have four-season weather; the similar Canadian tradition starts summer on Victoria Day one week prior and ends, as in the United States, on Labour Day. In Chinese astronomy, summer starts on or around 5 May, with the jiéqì known as lìxià, i.e. "establishment of summer", it ends on or around 6 August.
In southern and southeast Asia, where the monsoon occurs, summer is more defined as lasting from March, April and June, the warmest time of the year, ending with the onset of the monsoon rains. Because the temperature lag is shorter in the oceanic temperate southern hemisphere, most countries in this region use the meteorological definition with summer starting on 1 December and ending on the last day of February. Summer is traditionally associated with warm weather. In the Mediterranean regions, it is associated with dry weather, while in other places it is associated with rainy weather; the wet season is the main period of vegetation growth within the savanna climate regime. Where the wet season is associated with a seasonal shift in the prevailing winds, it is known as a monsoon. In the northern Atlantic Ocean, a distinct tropical cyclone season occurs from 1 June to 30 November; the statistical peak of the Atlantic hurricane season is 10 September. The Northeast Pacific Ocean has a broader period of activity, but in a similar time frame to the Atlantic.
The Northwest Pacific sees tropical cyclones year-round, with a minimum in February and March and a peak in early September. In the North Indian basin, storms are most common from April to December, with peaks in May and November. In the Southern Hemisphere, the tropical cyclone season runs from 1 November until the end of April with peaks in mid-February to early March. Thunderstorm season in the United States and Canada runs in the spring through summer; these storms can produce hail, strong winds and tornadoes during the afternoon and evening. Schools and universities have a summer break to take advantage of the warmer weather and longer days. In all countries, children are out of school during this time of year for summer break, although dates vary. In the United States, public schools end in late May in Memorial Day weekend, while colleges finish in early May, although some schools get out on the last or second last Thursday in May. In England and Wales, school resumes again in early September.
In Canada the summer holiday starts on the last or second-last Friday in June and ends in late August or on the first Monday of September, with the exception of when that date falls before Labour Day, in which case, ends on the second Monday of the month. In Russia the summer
The traditional China calendar, or Former Calendar, Traditional Calendar or Lunar Calendar, is a lunisolar calendar which reckons years and days according to astronomical phenomena. It is defined by GB/T 33661-2017, "Calculation and promulgation of the Chinese calendar", issued by the Standardisation Administration of China on 12 May 2017. Although modern day China uses the Gregorian calendar, the traditional Chinese calendar governs holidays in China and in overseas Chinese communities, it lists the dates of traditional Chinese holidays and guides people in selecting auspicious days for weddings, moving, or starting a business. Like Chinese characters, variants of this calendar are used in different parts of the Chinese cultural sphere. Korea and the Ryukyu Islands adopted the calendar, it evolved into Korean and Ryukyuan calendars; the main difference from the traditional Chinese calendar is the use of different meridians, which leads to some astronomical events—and calendar events based on them—falling on different dates.
The traditional Japanese calendar derived from the Chinese calendar, but its official use in Japan was abolished in 1873 as part of reforms after the Meiji Restoration. Calendars in Mongolia and Tibet have absorbed elements of the traditional Chinese calendar, but are not direct descendants of it. Days begin and end at midnight, months begin on the day of the new moon. Years begin on the second new moon after the winter solstice. Solar terms govern the end of each month. Written versions in ancient China included stems and branches of the year and the names of each month, including leap months as needed. Characters indicated whether a month was short; the traditional Chinese calendar was developed between 771 and 476 BC, during the Spring and Autumn period of the Eastern Zhou dynasty. Before the Zhou dynasty, solar calendars were used. One version of the solar calendar is the five-elements calendar. A 365-day year was divided into five phases of 73 days, with each phase corresponding to a Day 1 Wu Xing element.
A phase began followed by six 12-day weeks. Each phase consisted of two three-week months. Years began followed by a bǐngzǐ day and a 72-day fire phase. Other days were tracked using the Yellow River Map. Another version is a four-quarters calendar. Weeks were ten days long, with one month consisting of three weeks. A year had 12 months, with a ten-day week intercalated in summer as needed to keep up with the tropical year; the 10 Heavenly Stems and 12 Earthly Branches were used to mark days. A third version is the balanced calendar. A year was 365.25 days, a month was 29.5 days. After every 16th month, a half-month was intercalated. According to oracle bone records, the Shang dynasty calendar was a balanced calendar with 12 to 14 months in a year; the first lunisolar calendar was the Zhou calendar, introduced under the Zhou dynasty. This calendar set the beginning of the year at the day of the new moon before the winter solstice, it set the shàngyuán as the winter solstice of a dīngsì year, making the year it was introduced around 2,758,130.
Several competing lunisolar calendars were introduced by states fighting Zhou control during the Warring States period. The state of Lu issued its own Lu calendar. Jin issued the Xia calendar in AD 102, with a year beginning on the day of the new moon nearest the March equinox. Qin issued the Zhuanxu calendar, with a year beginning on the day of the new moon nearest the winter solstice. Song's Yin calendar began its year on the day of the new moon after the winter solstice; these calendars are known as the six ancient calendars, or quarter-remainder calendars, since all calculate a year as 365 1⁄4 days long. Months begin on the day of the new moon, a year has 12 or 13 months. Intercalary months are added to the end of the year; the Qiang and Dai calendars are modern versions of the Zhuanxu calendar, used by mountain peoples. After Qin Shi Huang unified China under the Qin dynasty in 221 BC, the Qin calendar was introduced, it followed most of the rules governing the Zhuanxu calendar, but the month order was that of the Xia calendar.
The intercalary month, known as the second Jiǔyuè, was placed at the end of the year. The Qin calendar was used into the Han dynasty. Emperor Wu of Han r. 141 – 87 BC introduced reforms halfway through his reign. His Taichu Calendar defined a solar year as 365 385⁄1539 days, the lunar month was 29 43⁄81 days; this calendar introduced the 24 solar terms. Solar terms were paired, with the 12 combined periods known as climate terms; the first solar term of the period was known as a pre-climate, the second was a mid-climate. Months were named for the mid-climat
Autumn known as fall in American English and sometimes in Canadian English, is one of the four temperate seasons. Autumn marks the transition from summer to winter, in September or March, when the duration of daylight becomes noticeably shorter and the temperature cools considerably. One of its main features in temperate climates is the shedding of leaves from deciduous trees; some cultures regard the autumnal equinox as "mid-autumn", while others with a longer temperature lag treat it as the start of autumn. Meteorologists use a definition based on Gregorian calendar months, with autumn being September and November in the northern hemisphere, March and May in the southern hemisphere. In North America, autumn traditionally starts on September 21 and ends on December 21, it is considered to end with the winter solstice. Popular culture in the United States associates Labor Day, the first Monday in September, as the end of summer and the start of autumn; as daytime and nighttime temperatures decrease, trees shed their leaves.
In traditional East Asian solar term, autumn starts on or around 8 August and ends on or about 7 November. In Ireland, the autumn months according to the national meteorological service, Met Éireann, are September and November. However, according to the Irish Calendar, based on ancient Gaelic traditions, autumn lasts throughout the months of August and October, or a few days depending on tradition; the names of the months in Manx Gaelic are based on autumn covering August and October. In Argentina and New Zealand, autumn begins on 1 March and ends on 31 May; the word autumn comes from the ancient Etruscan root autu- and has within it connotations of the passing of the year. It was borrowed by the neighbouring Romans, became the Latin word autumnus. After the Roman era, the word continued to be used as the Old French word autompne or autumpne in Middle English, was normalised to the original Latin. In the Medieval period, there are rare examples of its use as early as the 12th century, but by the 16th century, it was in common use.
Before the 16th century, harvest was the term used to refer to the season, as it is common in other West Germanic languages to this day. However, as more people moved from working the land to living in towns, the word harvest lost its reference to the time of year and came to refer only to the actual activity of reaping, autumn, as well as fall, began to replace it as a reference to the season; the alternative word fall for the season traces its origins to old Germanic languages. The exact derivation is unclear, with the Old English fiæll or feallan and the Old Norse fall all being possible candidates. However, these words all have the meaning "to fall from a height" and are derived either from a common root or from each other; the term came to denote the season in 16th-century England, a contraction of Middle English expressions like "fall of the leaf" and "fall of the year". During the 17th century, English emigration to the British colonies in North America was at its peak, the new settlers took the English language with them.
While the term fall became obsolete in Britain, it became the more common term in North America. The name backend, a once common name for the season in Northern England, has today been replaced by the name autumn. Association with the transition from warm to cold weather, its related status as the season of the primary harvest, has dominated its themes and popular images. In Western cultures, personifications of autumn are pretty, well-fed females adorned with fruits and grains that ripen at this time. Many cultures feature autumnal harvest festivals the most important on their calendars. Still extant echoes of these celebrations are found in the autumn Thanksgiving holiday of the United States and Canada, the Jewish Sukkot holiday with its roots as a full-moon harvest festival of "tabernacles". There are the many North American Indian festivals tied to harvest of ripe foods gathered in the wild, the Chinese Mid-Autumn or Moon festival, many others; the predominant mood of these autumnal celebrations is a gladness for the fruits of the earth mixed with a certain melancholy linked to the imminent arrival of harsh weather.
This view is presented in English poet John Keats' poem To Autumn, where he describes the season as a time of bounteous fecundity, a time of'mellow fruitfulness'. In North America, while most foods are harvested during the autumn, foods associated with the season include pumpkins and apples, which are used to make the seasonal beverage apple cider. Autumn in poetry, has been associated with melancholia; the possibilities and opportunities of summer are gone, the chill of winter is on the horizon. Skies turn grey, the amount of usable daylight drops and many people turn inward, both physically and mentally, it has been referred to as an unhealthy season. Similar examples may be found in Irish poet William Butler Yeats' poem The Wild Swans at Coole where the maturing season that the poet observes symbolically represents his own ageing self. Like the natural world that he observes, he too has reached his prime and now must look forward to the inevitability of old age and death. French p