Aries (♈︎) is the first astrological sign in the zodiac, spanning the first 30 degrees of celestial longitude, and originates from the Aries constellation. Under the tropical zodiac, the Sun transits this sign from approximately March 21 to April 19 each year. This time-duration is exactly the first month of the Solar Hijri calendar.

Western astrology is the system of astrology most popular in Western countries. Western astrology is historically based on Ptolemy's Tetrabiblos, which in turn was a continuation of Hellenistic and ultimately Babylonian traditions.