If you follow the neo-pagan movement, you'll recognize May 1 as the festival of Beltaine, or May Day. It was considered, so we're told by the neo-pagans, as the beginning of summer among the early peoples of Europe. The holiday officially begins at sundown the night before. Essentially it's a fertility festival, and a celebration and invocation of the hoped for fecundity of the growing season. Today certainly gave the eager denizens of gotham a taste of summer.
May all your dreams and labors bear the choicest fruit!