when is official day of summer
This year, the last day of summer is Sept. 22. Photo: GETTY IMAGES. Labor Day marks the ceremonial end of summer, but there are still a good few weeks to enjoy the season, even after the three-day weekend ends and schools begin their calendar year. This year, the last day of summer is officially on Sept. 22. The fall equinox arrives Sept. 23 and so does the onset of shorter days in the Northern Hemisphere. Equinox is derived from the Latin words aequus, which means equal, and nox, the word for night.
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.