When Is The First Day Of Autumn 2024 Uk. Autumn’s first day can fall on two different dates, depending on whether you use the meteorological or the astronomical definition. In 2024, the autumnal (fall) equinox arrives on sunday, september 22, marking the official first day of fall.

In 2023, the autumn equinox will be on saturday 23 september, at precisely. The first day of autumn often called fall (september equinox or autumnal equinox) is when the sun shines directly on the celestial equator passing from north to south and the.