Weather forecast September: Meteorological autumn begins today - what is the weather forecast for September?

Today (September 1) is the start of meteorological autumn. In the meteorological calendar, autumn will always start on September 1 and end on November 30.

The other way to define the start of the season is astronomical autumn, which will begin on September 22 and end on December 21 this year.

What is meteorological autumn?

Meteorological autumn (September 1 to November 30) is part of a fixed date system.

The meteorological seasons are four periods of the year made up of three months each.

The seasons are split to coincide with the Gregorian calendar, making it easier for meteorological observing and forecasting to compare seasonal and monthly statistics.

What is astronomical autumn?

Astronomical autumn is determined by the Earth’s orbit around the Sun and its axial tilt. It begins with the autumn equinox, which typically falls on September 22 or 23. During the equinox, the Sun shines directly on the equator, resulting in nearly equal day and night lengths across the globe.

This year, astronomical autumn will begin on September 22 and end on December 21.

What is the Met Office forecast for September?

Met Office UK five-day forecast

September 1 day

A day of sunny spells and showers. Some of the showers will be heavy, with the risk of hail and thunder. Blustery for many, but especially in and around passing showers. Feeling a little cooler than Sunday.

September 1 night

Showers tending to ease a little through the evening and overnight. A band of heavy rain will move into southwest England and the far south of Wales come dawn.

September 2

Rain will move eastwards across southern counties of England and Wales. Elsewhere will see a mixture of sunny spells and scattered showers. Lighter winds and maximum temperatures near average.

September 3 to September 5

Brisk winds and heavy rain likely on Wednesday, followed by sunny spells and heavy showers on Thursday. Perhaps a drier and brighter day for many on Friday. Average around temperatures.

Met Office long-range forecast

September 5 to September 14

Changeable weather conditions are expected across the UK during this period with low pressure systems tending to dominate the overall pattern. This will mean showers or longer spells of rain will affect much of the UK at times. Some heavy rain or showers are expected in places, most often in the west. Thunderstorms and hail are also possible, as are some spells of strong winds if any deep areas of low pressure form in the vicinity of the UK. Some short-lived spells of drier and more settled weather are also possible at times, especially early and again late in the period, when they may last a little longer. Temperatures will likely be close to average or slightly below overall, but may rise above at times in any drier, sunnier spells.

September 15 to September 29

Low pressure is likely to dominate much of this period, bringing changeable weather conditions with showers or some longer spells of rain at times. There will likely be some drier, more settled interludes, particularly at the start of the period. Temperatures are likely to be close to average, perhaps turning warmer than average later in the period.