How many days until fall?
320 days
- Begins
- Thursday
- Ends
- Monday, December 20
- Season length
- 89 days
- Meteorological start
- September 1
Astronomical — the solstices and equinoxes
Tied to the Earth's tilt, so the date shifts a day or two each year. This is the definition almanacs and calendars use.
Meteorological — whole calendar months
Fixed every year, so climate records can be compared like for like. This is the definition weather services use, and it is 22 days earlier.
Why the seasons are not equal
The four seasons from here
| Season | Begins | Length | Days away |
|---|---|---|---|
| Winter | December 21, 2026 | 89 days | 44 |
| Spring | March 20, 2027 | 93 days | 133 |
| Summer | June 21, 2027 | 94 days | 226 |
| Fall | September 23, 2027 | 89 days | 320 |
About fall
Astronomical fall runs from Thursday, September 23, 2027 to Monday, December 20, 2027, which is 89 days. The seasons are not equal lengths: the Earth’s orbit is an ellipse and it moves slowest near aphelion in early July, so it spends several days longer covering the half of its orbit between the March and September equinoxes. Northern spring and summer are the long ones.
Meteorological fall starts on September 1 and always covers three whole months. Weather services use it because a season of fixed length can be compared year to year; almanacs and calendars use the astronomical one. Neither is wrong — they answer different questions, which is why “the first day of fall” has two defensible answers.