The end of summer in 2025, according to the astronomical definition, is on Monday, September 22, 2025. This corresponds with the autumnal equinox, marking the official start of fall in the Northern Hemisphere. Meteorologically, summer ends earlier, on August 31, 2025, as meteorological summer spans the full months of June, July, and August.
Definitions of Summer End
- Astronomical Summer End: September 22, 2025, at the autumnal equinox, when day and night lengths are roughly equal and the seasons transition.
- Meteorological Summer End: August 31, 2025, marking the end of the calendar months June, July, and August considered as summer.
Thus, the most commonly recognized official end of the summer season in 2025 is September 22. However, many consider the meteorological summer ending on August 31 for practical weather and climate reporting purposes.
