Sunset Autumn Equinox 2025 Uk. Find london march and september equinox, june and december solstice seasons time and date like winter solstice, summer solstice, spring equinox, fall equinox. Usually, when we talk about the first day of autumn we are referring to the astronomical autumn which is defined by the earth's axis and orbit around the sun.
But keep in mind that the above dates are given in gmt, so they may differ in other time zones. In 2025 the autumnal equinox will occur on 22 september at 18.20 gmt (19.20 bst).