Summer officially ends on the date of the autumnal equinox, which in 2025 falls on Monday, September 22. This marks the end of astronomical summer in the Northern Hemisphere. There are two main definitions of summer end:
- Astronomical summer ends with the autumn equinox, occurring between September 21 and 24 each year. For 2025, this is September 22.
- Meteorological summer is based on calendar months and ends August 31.
So, in the most widely recognized official sense, summer 2025 ends on September 22.
