Fall, or autumn, begins with the autumnal equinox, which in the Northern Hemisphere is usually around September 22 or 23. For 2025, the autumnal equinox—the official start of fall—occurs on Monday, September 22 at 2:19 p.m. EDT (18:19 UTC).

There are two common definitions of when fall begins:

• The astronomical definition marks fall starting at the autumnal equinox and lasting until the winter solstice in December (around September 22 to December 21).

• The meteorological definition simply uses fixed calendar months, stating fall encompasses September, October, and November, starting always on September 1 and ending November 30.

In popular culture (especially in the US), fall often feels like it begins after Labor Day in early September, but astronomically, it officially begins at the equinox in late September.

So, for the current year 2025, the official start of fall is September 22, 2025.