When Will The Fall Equinox Happen 2024. The fall equinox occurs in the northern hemisphere on monday, september 22, 2020. The september equinox marks the beginning of fall in the northern hemisphere and the first day of spring in the southern hemisphere.

The autumn, or fall, equinox will happen at 8:43 a.m. Somewhere between september 21st to september 24th each year, there will be a moment when the day and the night will last approximately the same.