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 contains the summer solstice in the Northern Hemisphere, the day with the most daylight hours, and the winter solstice in the Southern Hemisphere, the day with the fewest daylight hours (excluding polar regions in both cases). 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 traditional astronomical summer is 21 June (meteorological summer begins on 1 June). In the Southern hemisphere, meteorological winter begins on 1 June.