June ( ) is the sixth month of the year in the Julian and Gregorian calendars and one of the four months with a length of 30 days. June is the month with the longest daylight hours of the year in the Northern Hemisphere and the shortest daylight hours of the year in the Southern Hemisphere. June in the Northern Hemisphere is the seasonal equivalent to December in the Southern Hemisphere and vice versa. In the Northern hemisphere, the beginning of the astronomical summer is 21 June (meteorological summer begins on 1 June). In the Southern hemisphere, the beginning of the astronomical winter is 21 June (meteorological winter begins on 1 June).