When does autumn start in 2023? Astronomical and meteorological dates for autumn according to the Met Office

There are two dates which mark the start of autumn every year; one is defined by the Earth’s axis and orbit around the sun and the second is a fixed meteorological date for consistent spacing and lengths of the seasons.

When does autumn officially start and end?

According to the Met Office, the first day of autumn is normally connected to the astronomical autumn which is determined by the Earth’s axis and orbit around the sun.

This year, astronomical autumn starts on Saturday, September 23 and ends on Thursdday, December 21.

The astronomical calendar is defined by the seasons due to the 23.5 degrees of tilt of the Earth’s rotational axis in relation to its orbit around the sun.

Both equinoxes and solstices are also connected with the Earth’s orbit around the sun.

Meteorological seasons are acquired by splitting the year into four time periods made up of three calendar months each.

These seasons are separated to coincide with the Gregorian calendar, making it easier for meteorological observing and predicting to compare seasonal and monthly statistics.

According to the meteorological calendar, the first day of autumn is always September 1 and ends on November 30.

The autumn season is defined by three months: September, October and November.