April Fool's Day, also known as April Fool's Day, is a traditional folk festival in western society and is celebrated on April 1 day every year. April Fool's Day is similar to the fun festival in ancient Rome and the joy festival in India. The timing is related to the "vernal equinox" (March 2 1), because the weather often changes suddenly during this period, just like nature is fooling human beings. On this day, people play jokes on people around them in various ways, but it can only be opened until noon 12 at the latest, which is a strict rule established by convention.