A heat map is a graphical representation of data where the individual values contained in a matrix are represented as colors. "Heat map" is a newer term but shading matrices have existed for over a century. Heat maps originated in 2D displays of the values in a data matrix. Larger values were represented by small dark gray or black squares and smaller values by lighter squares. Loua used a shading matrix to visualize social statistics across the districts of Paris. Sneath displayed the results of a cluster analysis by permuting the rows and the columns of a matrix to place similar values near each other according to the clustering. Jacques Bertin used a similar representation to display data; the idea for joining cluster trees to the rows and columns of the data matrix originated with Robert Ling in 1973. Ling used overstruck printer characters to represent different shades of gray, one character-width per pixel. Leland Wilkinson developed the first computer program in 1994 to produce cluster heat maps with high-resolution color graphics.
The Eisen et al. display shown in the figure is a replication of the earlier SYSTAT design. Software designer Cormac Kinney trademarked the term'heat map' in 1991 to describe a 2D display depicting financial market information; the company that acquired Kinney's invention in 2003 unintentionally allowed the trademark to lapse. There are different kinds of heat maps: Biology heat maps are used in molecular biology to represent the level of expression of many genes across a number of comparable samples as they are obtained from DNA microarrays; the tree map is a 2D hierarchical partitioning of data. A mosaic plot is a tiled heat map for representing a higher-way table of data; as with treemaps, the rectangular regions in a mosaic plot are hierarchically organized. The means. Friendly surveys the usage of this graph. A density function visualization is a heat map for representing the density of dots in a map, it enables one to perceive density of points independently of the zoom factor. Perrot et al proposed a way to use density function to visualize billions and billions of dots using big data infrastructure with Spark and Hadoop.
Many different color schemes can be used to illustrate the heat map, with perceptual advantages and disadvantages for each. Rainbow color maps are used, as humans can perceive more shades of color than they can of gray, this would purportedly increase the amount of detail perceivable in the image. However, this is discouraged by many in the scientific community, for the following reasons: The colors lack the natural perceptual ordering found in grayscale or blackbody spectrum colormaps. Common colormaps have uncontrolled changes in luminance that prevent meaningful conversion to grayscale for display or printing; this distracts from the actual data, arbitrarily making yellow and cyan regions appear more prominent than the regions of the data that are most important. The changes between colors lead to perception of gradients that aren't present, making actual gradients less prominent, meaning that rainbow colormaps can obscure detail in many cases rather than enhancing it. Choropleth maps are sometimes incorrectly referred to as heat maps.
False color Bertin, J.. Sémiologie Graphique. Les diagrammes, les réseaux, les cartes. Gauthier-Villars. OCLC 2656278. Eisen, M. B.. "Cluster analysis and display of genome-wide expression patterns". Proceedings of the National Academy of Sciences of the United States of America. 95: 14863–14868. Bibcode:1998PNAS...9514863E. Doi:10.1073/pnas.95.25.14863. PMC 24541. PMID 9843981. Friendly, Michael. "Mosaic Displays for Multi-Way Contingency Tables". Journal of the American Statistical Association. 89: 190–200. Doi:10.1080/01621459.1994.10476460. JSTOR 2291215. Ling, Robert L.. "A computer generated aid for cluster analysis". Communications of the ACM. 16: 355–361. Doi:10.1145/362248.362263. Sneath, P. H. A.. "The Application of Computers to Taxonomy". Journal of General Microbiology. 17: 201–26. Doi:10.1099/00221287-17-1-201. PMID 13475686. Wilkinson, L.. Advanced Applications: Systat for DOS Version 6. SYSTAT. ISBN 978-0-13-447285-0. Perrot, A.. Large interactive visualization of density functions on big
Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric physics, with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not occur until the 18th century; the 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data, it was not until after the elucidation of the laws of physics and more the development of the computer, allowing for the automated solution of a great many equations that model the weather, in the latter half of the 20th century that significant breakthroughs in weather forecasting were achieved. An important domain of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects include atmospheric interactions with large bodies of water. Meteorological phenomena are observable weather events that are explained by the science of meteorology.
Meteorological phenomena are described and quantified by the variables of Earth's atmosphere: temperature, air pressure, water vapour, mass flow, the variations and interactions of those variables, how they change over time. Different spatial scales are used to describe and predict weather on local and global levels. Meteorology, atmospheric physics, atmospheric chemistry are sub-disciplines of the atmospheric sciences. Meteorology and hydrology compose the interdisciplinary field of hydrometeorology; the interactions between Earth's atmosphere and its oceans are part of a coupled ocean-atmosphere system. Meteorology has application in many diverse fields such as the military, energy production, transport and construction; the word meteorology is from the Ancient Greek μετέωρος metéōros and -λογία -logia, meaning "the study of things high in the air". The ability to predict rains and floods based on annual cycles was evidently used by humans at least from the time of agricultural settlement if not earlier.
Early approaches to predicting weather were practiced by priests. Cuneiform inscriptions on Babylonian tablets included associations between rain; the Chaldeans differentiated 46 ° halos. Ancient Indian Upanishads contain mentions of seasons; the Samaveda mentions sacrifices to be performed. Varāhamihira's classical work Brihatsamhita, written about 500 AD, provides evidence of weather observation. In 350 BC, Aristotle wrote Meteorology. Aristotle is considered the founder of meteorology. One of the most impressive achievements described in the Meteorology is the description of what is now known as the hydrologic cycle; the book De Mundo noted If the flashing body is set on fire and rushes violently to the Earth it is called a thunderbolt. They are all called ` swooping bolts'. Lightning is sometimes smoky, is called'smoldering lightning". At other times, it travels in crooked lines, is called forked lightning; when it swoops down upon some object it is called'swooping lightning'. The Greek scientist Theophrastus compiled a book on weather forecasting, called the Book of Signs.
The work of Theophrastus remained a dominant influence in the study of weather and in weather forecasting for nearly 2,000 years. In 25 AD, Pomponius Mela, a geographer for the Roman Empire, formalized the climatic zone system. According to Toufic Fahd, around the 9th century, Al-Dinawari wrote the Kitab al-Nabat, in which he deals with the application of meteorology to agriculture during the Muslim Agricultural Revolution, he describes the meteorological character of the sky, the planets and constellations, the sun and moon, the lunar phases indicating seasons and rain, the anwa, atmospheric phenomena such as winds, lightning, floods, rivers, lakes. Early attempts at predicting weather were related to prophecy and divining, were sometimes based on astrological ideas. Admiral FitzRoy tried to separate scientific approaches from prophetic ones. Ptolemy wrote on the atmospheric refraction of light in the context of astronomical observations. In 1021, Alhazen showed that atmospheric refraction is responsible for twilight.
St. Albert the Great was the first to propose that each drop of falling rain had the form of a small sphere, that this form meant that the rainbow was produced by light interacting with each raindrop. Roger Bacon was the first to calculate the angular size of the rainbow, he stated. In the late 13th century and early 14th century, Kamāl al-Dīn al-Fārisī and Theodoric of Freiberg were the first to give the correct explanations for the primary rainbow phenomenon. Theoderic went further and explained the secondary rainbow. In 1716, Edmund Halley suggested that aurorae are caused by "magnetic effluvia" moving along the Earth's magnetic field lines. In 1441, King Sejong's son, Prince Munjong of Korea, invented the first standardized rain gauge; these were sent throughout the Joseon dynasty of Korea as an official tool to assess land taxes based
The Met Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business and Industrial Strategy led by CEO, Penelope Endersby, who took on the role as Chief Executive in December 2018, the first woman to do so; the Met Office makes meteorological predictions across all timescales from weather forecasts to climate change. The Met Office was established in 1854 as a small department within the Board of Trade under Vice Admiral Robert FitzRoy as a service to mariners; the loss of the passenger vessel, the Royal Charter, 459 lives off the coast of Anglesey in a violent storm in October 1859 led to the first gale warning service. FitzRoy established a network of 15 coastal stations from which visual gale warnings could be provided for ships at sea; the new electric telegraph enabled rapid dissemination of warnings and led to the development of an observational network which could be used to provide synoptic analysis. The Met Office started in 1861 to provide weather forecasts to newspapers.
FitzRoy requested the daily traces of the photo-barograph at Kew Observatory to assist in this task and similar barographs and as well as instruments to continuously record other meteorological parameters were provided to stations across the observing network. Publication of forecasts ceased in May 1866 after FitzRoy's death but recommenced in April 1879. Following the First World War, the Met Office became part of the Air Ministry in 1919, the weather observed from the top of Adastral House giving rise to the phrase "The weather on the Air Ministry roof"; as a result of the need for weather information for aviation, the Met Office located many of its observation and data collection points on RAF airfields, this accounts for the large number of military airfields mentioned in weather reports today. In 1936 the Met Office split with services to the Royal Navy being provided by its own forecasting services, it became an executive agency of the Ministry of Defence in April 1990, a quasi-governmental role, being required to act commercially.
Following a machinery of government change, the Met Office became part of the Department for Business and Skills on 18 July 2011, subsequently part of the Department for Business and Industrial Strategy following the merger of BIS and the Department of Energy and Climate Change on 14 July 2016. Although no longer part of the MOD, the Met Office maintains strong links with the military through its front line offices at RAF and Army bases both in the UK and overseas and its involvement in the Joint Operations Meteorology and Oceanography Centre with the Royal Navy; the Mobile Met Unit are a unit consisting of Met Office staff who are RAF reservists who accompany forward units in times of conflict advising the armed forces of the conditions for battle the RAF. In September 2003 the Met Office moved its headquarters from Bracknell in Berkshire to a purpose-built £80m structure at Exeter Business Park, near junction 29 of the M5 motorway; the new building was opened on 21 June 2004 – a few weeks short of the Met Office's 150th anniversary – by Robert May, Baron May of Oxford.
It has a worldwide presence – including a forecasting centre in Aberdeen, offices in Gibraltar and on the Falklands. Other outposts lodge in establishments such as the Joint Centre for Mesoscale Meteorology at University of Reading in Berkshire, the Joint Centre for Hydro-Meteorological Research site at Wallingford in Oxfordshire, there is a Met Office presence at Army and Air Force bases within the UK and abroad. Royal Navy weather forecasts are provided by naval officers, not Met Office personnel; the Shipping Forecast is produced by the Met Office and broadcast on BBC Radio 4, for those traversing the seas around the British Isles. The Met Office issues Severe Weather Warnings for the United Kingdom through the National Severe Weather Warning Service; these warn of weather events that may endanger people's lives. In March 2008, the system was improved and a new stage of warning was introduced, the'Advisory'. In September 2015 the Met Office established a "name our storms" project, the aim is to provide a single authoritative naming system for the storms that affect the UK and Ireland by asking the public to suggest names.
On 10 November, the first named. The main role of the Met Office is to produce forecast models by gathering information from weather satellites in space and observations on earth processing it with a variety of models, based on a software package known as the unified model; the principal weather products for UK customers are 36-hour forecasts from the operational 1.5 km resolution UKV model covering the UK and surroundings, 48-hour forecasts from the 12 km resolution NAE model covering Europe and the North Atlantic, 144-hour forecasts from the 25 km resolution global model. The Met Office's Global Model forecast has been in the top 3 for global weather forecast performance in independent verification to WMO standards. Products for other regions of the globe are sold to customers abroad, provided for MOD operations abroad or provided free to developing countries in Africa. If necessary, forecasters may make adjustments to the computer forecasts. Data is stored in the Met Office's own PP-format.
Formed in 2009, the Flood Forecasting Centre is a joint venture between the Environment Agency and the Met Office to provide flood risk guidance for Engl
Gordon Valentine Manley, FRGS was an English climatologist, described as "probably the best known, most prolific and most expert on the climate of Britain of his generation". He assembled the Central England temperature series of monthly mean temperatures stretching back to 1659, the longest standardised instrumental record available for anywhere in the world, it provides a benchmark for proxy records of climatic change for the period covered, is a notable example of scientific scholarship and perseverance. His two papers describing the work are available online. Gordon Manley was born at Isle of Man, he was brought up in Blackburn, where he attended Queen Elizabeth's Grammar School. After obtaining degrees in engineering and geography at Victoria University of Manchester and Gonville and Caius College, Cambridge Manley joined the Meteorological Office in 1925, but resigned the following year. In the summer of 1926 he was a member of the Cambridge Expedition to East Greenland, which carried out much important research.
That same year he began a lengthy career in academia when he became an assistant lecturer in geography at Birmingham University. His enthusiasm for his subject, his joy of learning and his wit made him an excellent teacher. In 1928 he was appointed a lecturer in geography at the University of Durham, he subsequently became a Senior Lecturer and founding Head of Department and Director of the University's Observatory. He became Curator of Durham University Observatory in 1931, where he did much work on standardising the long temperature record that dated back to the mid-nineteenth century; the following year, he started collecting data at Moor House in the northern Pennines. He subsequently established a meteorological station close to the summit of Great Dun Fell at 847m, which recorded data at three-hour intervals from 1938 to 1940; this was the first series of mountain observations to be made in England. From 1937 he carried out valuable research into the Helm Wind, a north-east wind that the local topography causes to blow down the south-west slope of Cross Fell in the Pennines with unusual strength.
Manley interpreted the phenomenon in hydrodynamic terms as a "standing wave" and "rotor", a model confirmed in 1939 by glider flights. In 1939 he left Durham to become a Demonstrator in Geography at Cambridge University. From 1942 to 1945 he was a Flight Lieutenant in Cambridge University Air Squadron, but he continued his research and teaching of students from Cambridge and Bedford College, London; the Royal Meteorological Society's magazine Weather, whose objective was to make developments in meteorology accessible to a wider public, started in 1946 during his presidency and benefited from his encouragement. From 1948 to 1964, Manley was Professor of Geography at Bedford College for Women in the University of London, he maintained his links with Cambridge, one result being the joint participation of undergraduates from both institutions in expeditions to Norway and Iceland. In 1952 Collins published his Climate and the British Scene in their New Naturalist series; this book accessible to the non-academic reader, was one of his greatest contributions to British climatology.
His flair for writing entertainingly as well as informatively about the climate helped him to write a long series of articles for the Manchester Guardian from 1952 onwards about weather and climate events that were of topical interest. In 1964, at the age of 62, he took on the challenge of founding the new department of Environmental Studies at the new Lancaster University. In 1967 he retired and moved back to Cambridge. During this period, his research on Manchester rainfall and on Central England temperatures was published; the Central England temperature series continues to be updated each month by the UK Meteorological Office. During 1969–70 he was a Visiting Professor of Meteorology at Texas A&M University. For the rest of his life he continued publishing. In all he wrote 182 papers from 1927 onwards. At the time of his death he was assembling instrumental data for the north of England and Scotland back to the 18th century, he is buried in Coton churchyard. Note: The second and third items are those referred to in the footnote above and are available online.
They are large PDF files. Manley, Gordon. Climate and the British Scene: New Naturalist No. 22, Collins, 1952. Manley, G. "The mean temperature of central England, 1698–1952." Quarterly Journal of the Royal Meteorological Society, vol. 79, pp. 242–261. Manley, G. "Central England temperatures: monthly means 1659 to 1973", Quarterly Journal of the Royal Meteorological Society, vol. 100, pp. 389–405. BSc in engineering, Manchester University BA in geography and Caius College, Cambridge Appointed Fellow of the Royal Geographical Society Appointed Fellow of the Royal Meteorological Society MSc, Manchester University Buchan Prize of the Royal Meteorological Society Gave the GJ Symons Memorial Lecture President of the Royal Meteorological Society Awarded the Murchison Grant of the Royal Geographical Society Member of the council of the Royal Geographical Society DSc, Manchester University Made Honorary Fellow of the Royal Meteorological Society DSc honoris causa, Durham University On 22 May 2007, the Gordon_Manley Building, named in his honour, was opened at the Lancaster Environment Centre by Lord Rees of Ludlow Kt.
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Geoffrey Philip Eden FRMetS was a leading British weather journalist and weather historian. Philip Eden studied a BA in Geography before gaining a masters in applied meteorology and climatology at Birmingham University in 1972, he worked for some time in the 1980s for Noble Denton and Associates in their meteorology department. It was during this period, his career as a radio weather presenter began with the London station LBC in 1983. He was subsequently chief network weather presenter for BBC Radio 5 Live from 1994 to 2005, he wrote a weekly column for the Sunday Telegraph from 1986 until forced to cease because of ill-health in 2015, had a daily "Weather Watch" column in the Daily Telegraph from 1998 to 2012. Eden wrote monthly look-backs for WeatherOnline, he authored a number of books on British climate. Philip Eden was Vice President of the Royal Meteorological Society from 2007 to 2009. Eden was awarded the Royal Meteorological Society's Gordon Manley Weather Prize in 2000; the prize is awarded annually for any outstanding contribution to Weather through a paper or papers, or other outstanding service to Weather, in the preceding five years that has furthered the public understanding of meteorology and oceanography.
He was Director of the Chilterns Observatory Trust from 2007. In the last few years of his life he was suffering from Lewy body dementia
Temperature is a physical quantity expressing hot and cold. It is measured with a thermometer calibrated in one or more temperature scales; the most used scales are the Celsius scale, Fahrenheit scale, Kelvin scale. The kelvin is the unit of temperature in the International System of Units, in which temperature is one of the seven fundamental base quantities; the Kelvin scale is used in science and technology. Theoretically, the coldest a system can be is when its temperature is absolute zero, at which point the thermal motion in matter would be zero. However, an actual physical system or object can never attain a temperature of absolute zero. Absolute zero is denoted as 0 K on the Kelvin scale, −273.15 °C on the Celsius scale, −459.67 °F on the Fahrenheit scale. For an ideal gas, temperature is proportional to the average kinetic energy of the random microscopic motions of the constituent microscopic particles. Temperature is important in all fields of natural science, including physics, Earth science and biology, as well as most aspects of daily life.
Many physical processes are affected by temperature, such as physical properties of materials including the phase, solubility, vapor pressure, electrical conductivity rate and extent to which chemical reactions occur the amount and properties of thermal radiation emitted from the surface of an object speed of sound is a function of the square root of the absolute temperature Temperature scales differ in two ways: the point chosen as zero degrees, the magnitudes of incremental units or degrees on the scale. The Celsius scale is used for common temperature measurements in most of the world, it is an empirical scale, developed by a historical progress, which led to its zero point 0 °C being defined by the freezing point of water, additional degrees defined so that 100 °C was the boiling point of water, both at sea-level atmospheric pressure. Because of the 100-degree interval, it was called a centigrade scale. Since the standardization of the kelvin in the International System of Units, it has subsequently been redefined in terms of the equivalent fixing points on the Kelvin scale, so that a temperature increment of one degree Celsius is the same as an increment of one kelvin, though they differ by an additive offset of 273.15.
The United States uses the Fahrenheit scale, on which water freezes at 32 °F and boils at 212 °F at sea-level atmospheric pressure. Many scientific measurements use the Kelvin temperature scale, named in honor of the Scots-Irish physicist who first defined it, it is a absolute temperature scale. Its zero point, 0 K, is defined to coincide with the coldest physically-possible temperature, its degrees are defined through thermodynamics. The temperature of absolute zero occurs at 0 K = −273.15 °C, the freezing point of water at sea-level atmospheric pressure occurs at 273.15 K = 0 °C. The International System of Units defines a scale and unit for the kelvin or thermodynamic temperature by using the reliably reproducible temperature of the triple point of water as a second reference point; the triple point is a singular state with its own unique and invariant temperature and pressure, along with, for a fixed mass of water in a vessel of fixed volume, an autonomically and stably self-determining partition into three mutually contacting phases, vapour and solid, dynamically depending only on the total internal energy of the mass of water.
For historical reasons, the triple point temperature of water is fixed at 273.16 units of the measurement increment. There is a variety of kinds of temperature scale, it may be convenient to classify them theoretically based. Empirical temperature scales are older, while theoretically based scales arose in the middle of the nineteenth century. Empirically based temperature scales rely directly on measurements of simple physical properties of materials. For example, the length of a column of mercury, confined in a glass-walled capillary tube, is dependent on temperature, is the basis of the useful mercury-in-glass thermometer; such scales are valid only within convenient ranges of temperature. For example, above the boiling point of mercury, a mercury-in-glass thermometer is impracticable. Most materials expand with temperature increase, but some materials, such as water, contract with temperature increase over some specific range, they are hardly useful as thermometric materials. A material is of no use as a thermometer near one of its phase-change temperatures, for example its boiling-point.
In spite of these restrictions, most used practical thermometers are of the empirically based kind. It was used for calorimetry, which contributed to the discovery of thermodynamics. Empirical thermometry has serious drawbacks when judged as a basis for theoretical physics. Empirically based thermometers, beyond their base as simple direct measurements of ordinary physical properties of thermometric materials, can be re-calibrated, by use of theoretical physical reasoning, this can extend their range of adequacy. Theoretically-based temperature scales are based directly on theoretical arguments those of thermodynamics, kinetic theory and quantum mechanics, they rely on theoretical properties of idealized materials. They are more or less comparable with feasible physical devices and materials. Theoretically based temperature scales are used to provide calibrating standards for practi
Climate of the United Kingdom
The United Kingdom straddles the higher mid-latitudes between 49° and 61° N. It is on the western seaboard of the world's largest land mass. Since the UK is always in or close to the path of the polar front jet stream, frequent changes in pressure and unsettled weather are typical. Many types of weather can be experienced in a single day. In general the climate of the UK is cool and cloudy, high temperatures are infrequent; the climate in the United Kingdom is defined as a temperate oceanic climate, or Cfb on the Köppen climate classification system, a classification it shares with most of north-west Europe. Regional climates are influenced by latitude. Northern Ireland and western parts of England and Scotland, being closest to the Atlantic Ocean, are the mildest and windiest regions of the UK, temperature ranges here are extreme. Eastern areas are drier and less windy, experience the greatest daily and seasonal temperature variations. Northern areas are cooler and wetter, have larger temperature ranges than southern areas.
The UK is under the influence of the maritime polar air mass from the north-west. Northern Ireland and the west of Scotland are the most exposed to the maritime polar air mass which brings cool moist air; the south and south-east of England are the least exposed to polar air masses from the north-west, on occasion see continental tropical air masses from the south, which bring warm dry air in the summer. On average, the temperature ranges from 25-18 degrees. If the air masses are strong enough in their respective areas during the summer, there can sometimes be a large difference in temperature between the far north of Scotland and the south-east of England – a difference of 10–15 °C but sometimes as much as 20 °C or more. In the height of summer the Northern Isles could have temperatures around 15 °C and areas around London could reach 36 °C. England has higher maximum and minimum temperatures than the other areas of the UK, though Wales has higher minima from November to February, Northern Ireland has higher maxima from December to February.
England is sunnier throughout the year, but unlike Wales, Northern Ireland and Scotland, the sunniest month is July, with an average of 193.5 hours. It rains on fewer days in every month throughout the year than the rest of the UK, rainfall totals are less in every month, with the driest month, averaging 58.4 mm. The climate of south-west England displays a seasonal temperature variation, although it is less extreme than most of the United Kingdom. Gales are less common in England compared to Scotland; some events such as the Great Storm of 1987 caused damage in England. The prevailing wind direction for England is from the south-west; the highest temperature recorded in England occurred on 10 August 2003 in Kent. The lowest temperature recorded in England occurred on 10 January 1982 in Newport, Shropshire. Northern Ireland is warmer than Scotland throughout the year. Maximum temperatures are milder than in Wales from December to April, milder than in England from December to February, but Northern Ireland is cooler during the rest of the year.
Sunshine totals in every month are more than those of Scotland, but less than those of the rest of Great Britain. Northern Ireland is drier and has fewer rainy days than Scotland throughout the year, except in May, when it rains on more days. Northern Ireland is drier than Wales in every month, yet it rains on more days; the rainiest month is January. Scotland is cool compared to the rest of the UK, the climate at altitude merges into Cfc on the Köppen system, with average minimum temperatures in January of −0.2 °C. The Central Lowlands have higher temperatures during the summer than any other part of Scotland, have broken some records for the whole of the UK. Aviemore is considered one of the coldest inhabited places, with its inland location and an altitude of about 210 metres; the wettest month in Scotland is January. Wales has warmer temperatures throughout the year than Northern Ireland and Scotland and has milder winter minima than England, but cooler winter maxima than Northern Ireland.
Wales is wetter throughout the year than Northern Ireland and England, but has fewer rainy days than Northern Ireland. Wales is drier than Scotland in every month apart from May and December, there are fewer days with rain than in Scotland. Sunshine totals throughout the year are more than that of Scotland and Northern Ireland, but less than that of neighbouring England. May is the sunniest month. Spring is the period from March to May. Spring is a calm, cool season because the Atlantic has lost much of its heat throughout the autumn and winter; as the sun rises higher in the sky and the days get longer, temperatures rise, but the solar effect is mitigated somewhat by the effect of the cool ocean waters and westerly winds that blow across them. There is a fair chance of snow earlier in the season; some of the country's heaviest snowfalls of recent years have happened in the first half of March, snow showers can occ