Autumn Equinox 2024 Time. Autumn equinox 2024 (beginning of astronomical autumn) on the day of the autumn (september) equinox, the sun, moving along the ecliptic, crosses the celestial equator, moving from the northern hemisphere to the southern. 1931 was the last time the autumn equinox happened on 24th september, and it’s not due again until 2303.

According to the meteorological calendar, the first autumn day is friday 1st september 2024. In 2024, the autumn equinox will occur on sunday, 22nd september.