The winter months of the civil year are December, January and February. The winter solstice is on December 21, or when the earth's axial tilt is farthest away from the sun. As a result, December 21 experiences the shortest amount of sunlight than any other days of the year. January 1 is the beginning of the new year, according to the Gregorian Calendar. February is an anomaly from other months since it only has 28 days. Every four years, February has 29 days since it is a leap year in the calendar; some recent leap years are 2000, 2004, 2008. Both December and January have 31 days.
March, April and May are recognized as the spring months of the civil year, according to the Gregorian calendar. The spring equinox, or when the Earth's axis is not tilted toward or away from the sun, is always on March 21. Similar to the fall equinox, sunlight occurs for exactly 12 hours on the spring equinox. After the spring equinox, though, the amount of sunlight per day grows between March 21 and the summer solstice since the sun continues to follow a higher path. March and May have 31 days, while April on has 30 days.
Although June, July and August are known as the summer months, the first official day of summer on the Gregorian calendar is June 21, or the summer solstice. On this day, the tilt of the Earth's axis is closest to the Sun. In the Northern Hemisphere, June 21 is the longest day of the year in terms of amount of sunlight and the sun is usually at its highest point in the sky on this day. However, the Southern Hemisphere experiences its winter solstice on June 21, since the Earth's southern axis is tilted away from the sun. June has 30 days. July and August both have 31 days.
The final season before the start of winter is the autumn, also known as fall, and comprises September, October and November. The primary solar marking of autumn is the autumnal equinox. Much like its spring counterpart, the Earth experiences 12 hours of sunlight on the autumnal equinox, which is September 22 or 23, depending on the year. Unlike the days following spring equinox, daylight decreases in the subsequent days after the autumnal equinox. September and November have 30 days, while October has 31 days.