May Day celebrations at Padstow , Cornwall 1 May 1974 The first day of the month of May is known as May Day. It is the time of year when warmer weather begins and flowers and trees start to blossom. It is said to be a time of love and romance. It is when people celebrate the coming of summer with lots of different customs that are expressions of joy and hope after a long winter. Although summer does not officially begin until June, May Day really marks its beginning. May Day celebrations have their origins in the Roman festival of Flora, goddess of fruit and flowers, which marked the beginning of summer