Seasonal
When Does Autumn Start in the UK 2026? Meteorological vs Astronomical Autumn Explained
When does autumn start in the UK in 2026? Meteorological autumn begins 1 September, the equinox falls on 23 September. Key dates, daylight and weather.
6 min readLondon loses close to four hours of daylight between the start of September and the end of October. That drain, more than any date on a calendar, is what makes autumn feel like autumn. But if you want an official start date for 2026, there are two: meteorological autumn begins on Tuesday 1 September 2026, and astronomical autumn begins at the equinox on Wednesday 23 September 2026.
This guide covers both definitions, the exact equinox moment, every key date between the August bank holiday and the end of November, and what UK autumn weather realistically delivers.
The Short Answer: Autumn 2026 Start Dates
| Definition | Start Date 2026 | End Date 2026 | Duration |
|---|---|---|---|
| Meteorological autumn | Tue 1 September | Mon 30 November | 91 days |
| Astronomical autumn | Wed 23 September (equinox) | Mon 21 December (winter solstice) | 89 days |
Neither date is more correct than the other. They exist for different reasons, and which one matters to you depends on whether you are comparing climate records or watching the sky.
Why Are There Two Autumns?
The meteorological calendar divides the year into four fixed three-month seasons built around the annual temperature cycle. September, October, and November are the transition months between the UK's warmest quarter and its coldest, so they are grouped as autumn. The Met Office uses these fixed blocks for all official climate statistics, because comparing "autumn 2026" with "autumn 1996" only works if both cover the same 91 days.
Astronomical autumn follows the Earth's orbit instead. It starts at the September equinox and ends at the December solstice, so the dates drift slightly from year to year. We covered the same split for summer in our when does summer start guide; the logic is identical, just pointing the other way.
The Autumn Equinox on 23 September
The 2026 autumnal equinox falls at 01:06 BST on Wednesday 23 September. At that moment the Sun crosses the celestial equator heading south, and day and night are close to equal everywhere on Earth.
Close, but not exactly equal. Because the atmosphere bends sunlight around the horizon and sunrise is measured from the Sun's upper edge, UK days on the equinox actually run about 12 hours and 10 minutes. The date when daylight and darkness genuinely match, called the equilux, arrives around 25 to 26 September at UK latitudes.
One quirk worth knowing: the equinox can fall on 22 or 23 September depending on the year, because the Earth's orbit is not a whole number of days. In 2026 it is firmly on the 23rd.
How Fast the Nights Draw In
The weeks around the equinox are when the UK sheds daylight fastest, roughly 4 minutes per day, and closer to 5 in northern Scotland. Here is what that does to London through autumn 2026.
Further north the squeeze is harder. Edinburgh starts September with nearly 14 hours of daylight and ends November with barely 7 and a half. If there are outdoor jobs you have been putting off all summer, September is the month to do them.
Key Autumn 2026 Dates for Your Calendar
| Date | Event |
|---|---|
| Mon 31 August | Summer bank holiday in England, Wales and NI, last day of meteorological summer |
| Tue 1 September | Meteorological autumn begins, new storm naming season opens |
| First week of September | Most schools in England and Wales return, new storm name list announced |
| Wed 23 September, 01:06 BST | Autumnal equinox, astronomical autumn begins |
| Sun 25 October, 02:00 | Clocks go back one hour, GMT returns |
| Sat 31 October | Halloween, on a Saturday this year |
| Thu 5 November | Bonfire Night |
| Mon 30 November | St Andrew's Day, last day of meteorological autumn |
Two of those dates do the heavy lifting for how autumn feels. The clocks going back on 25 October shifts sunset in London from roughly 5:45pm to 4:45pm overnight, which is the single biggest jolt in the whole season. And the August bank holiday on 31 August is the psychological end of summer for most households, whatever the thermometer says.
What Autumn Weather Actually Does
September: Summer's Encore
September is the most underrated month in the UK calendar. Sea temperatures peak in early September, the Atlantic storm track is usually still parked to the north, and settled spells are common. It can still be properly hot: September 2023 was the UK's joint warmest on record and produced seven consecutive days above 30C, the first time that had ever happened in a UK September.
October: The Atlantic Returns
October is when the jet stream typically strengthens and swings back towards the UK, and it carries an extra hazard: the remnants of Atlantic hurricanes. Ex-hurricane Ophelia in October 2017 is the modern benchmark, bringing 90mph gusts to Ireland and turning the UK sky orange with Saharan dust. Expect the first named storm conversations, the first proper gales, and rainfall totals that climb sharply in the west.
November: Fog, Frost and the First Taste of Winter
November brings the season's first widespread air frosts. Sheltered Scottish glens often record theirs in late September, but most towns in southern England wait until late October or November. Long nights and moist ground also make November the UK's peak month for dense fog, which is worth respecting on the morning commute more than any rain shower.
Storm Season and the New Name List
The UK storm naming season runs from early September to late August, run jointly by the Met Office, Met Eireann, and the Dutch met service KNMI. The 2026/27 name list will be announced in early September 2026, and you can watch for it at the Met Office storm centre.
Do not assume a named storm will wait for the dark months. Last season's first named storm, Amy, arrived at the start of October 2025 and we covered the pattern in our UK storm season guide. On average the first named storm of a season arrives in the autumn, not the winter.
Frequently Asked Questions
Is September a summer month or an autumn month?
Meteorologically, September is autumn from day one. Astronomically, summer runs until 23 September 2026. In practice, early September often feels like high summer, and the switch usually arrives with the first vigorous Atlantic front, not with either calendar date.
When do the nights start drawing in?
Daylight has been shrinking since the summer solstice on 21 June, but the loss accelerates through August and peaks around the September equinox at roughly 4 minutes a day. Most people notice it in the second half of September, when sunset in much of England slips before 7pm.
When do the clocks go back in 2026?
At 2:00am on Sunday 25 October 2026, when clocks move back one hour and British Summer Time ends. That morning you get an extra hour in bed; the trade is that sunset arrives before 5pm in most of the UK from that day onwards.
Will there be an Indian summer in 2026?
A warm settled spell in September or October is genuinely common, and forecasters cannot see one more than a week or two ahead. Seasonal outlooks issued in summer have very limited skill for UK autumn, so treat any confident October prediction with scepticism and check the forecast accuracy guide for what different lead times are worth.
When does autumn end?
Meteorological autumn ends on 30 November 2026, with winter starting on 1 December. Astronomical autumn runs until the winter solstice on Monday 21 December 2026, the shortest day of the year.
Make the Most of It
Autumn 2026 gives you a generous run-in: five full weeks between the August bank holiday and the end of September when daylight is still decent and the sea is at its warmest. Book the outdoor plans early in the season, treat October forecasts with respect, and keep a decent coat by the door from the equinox onwards. And on any given grey morning between now and December, the question is the same one it always is: do I need a brolly? Get a plain English answer for your town at doineedabrolly.co.uk.