September Equinox 2024. In the northern hemisphere, the autumnal equinox happens on september 22, 2024, at 12:44 gmt (08:44 a.m. Everything you need to know.

In 2024, the autumnal (fall) equinox arrives on sunday, september 22, marking the official first day of fall. Normally, the autumn equinox falls between 22 and 24 september, and this year the equinox occurs on 22 september at 13:44 bst.