The First Day of Summer (21-06-2011)

Summer is the hottest of the four temperate seasons, falling between spring and autumn. At the summer solstice, the days are long and the nights are shorter, with day-length decreasing as the season progresses after the solstice. The date of the beginning of summer varies according to climate, tradition and culture. When it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere, and vice versa. From an astronomical view, the equinoxes and solstices would be the middle of the respective seasons, but sometimes astronomical summer is defined as starting at the solstice, the time of maximal insolation, or on the traditional date of June 21.