April is the fourth month on the current Gregorian but the fifth month on the old Julian calendar. In the Northern Hemisphere, April is the beginning of spring in many places. In the Southern Hemisphere, April is the equivalent of October. The name April comes from the Latin word Aprilis and was the second month on the old Roman calendar that used to begin in March.
April was seen as a month of both sun and growth by the Romans, which may be how they came up with the name Aprilis. There may be some connection to the Greek goddess Aphrodite as well. Whatever its origin, the name stuck and has come to us as April. With winter over for most in the Northern Hemisphere, it was a time of joy. It started getting warmer, the cold days of rain, snow, and frost receded and replaced by much nicer days.
There are countless festivities in April to celebrate this time of year to be chronicled here. April Fools Day (1 April) is celebrated around the world as a day of playing pranks. It possibly goes back to a time when people, happy to see winter come to an end, would play joyful pranks on their family and friends. Whatever its source, it has become ingrained into culture and tradition. Easter and Passover are often celebrated in April as well.
For those interested, the birthstone for April is the diamond and the birth flowers are the daisy and sweet pea.