When Does Summer Really End?

9/18/2019 (Permalink)

Summer falls into September.

Summer is the season for basking in the warm sun and rejoicing in the freedom of summer vacation. So when the rest and relaxation is shooed away for cooler days and the start of school, it’s easy to forget that the summer season is far from over.

Many consider Labor Day the final hurrah of summer, but we still have a few weeks after that celebratory first Monday of September. Summer officially ends at the autumnal equinox, when the sun is at zenith, or directly above, the equator. After the autumnal equinox the sun moves south of the equator, leaving behind a chilly autumn in the Northern Hemisphere and beckoning in spring to the Southern Hemisphere.

The year is divided into the four seasons based on the two equinoxes and the two solstices. The summer and winter solstices, which typically land around June 21 and December 22, mark the shortest and the longest days of the year. The autumnal and vernal equinoxes, which fall around September 23 and March 21, mark the points in the year when the day and the night are of equal lengths. Hence the word equinox, from the Latin roots meaning “equal night.” Astronomically speaking, these four solar events mark the middle of the seasons rather than their beginning and ending, but we separate the year into meteorological seasons which reflect the average temperature patterns and climate.

Just as the summer solstice tends to fall a little ways into summer vacation, the autumnal equinox typically falls at the end of September, a few weeks into the school year and well after the Dog Days, the hottest period of the summer.

Are you ready for the start of autumn?