When Is the Autumn Equinox?
Find out when the autumn equinox is this year. Equal day and night, countdown, dates for the next 10 years, and harvest festival facts.
When the Autumn Equinox Falls
The autumn (autumnal) equinox in 2026 is on Tuesday 22 September. In 2027 it falls on Thursday 23 September, in 2028 again on 22 September, and the date oscillates between 22 and 23 September because the Earth's orbit is 365.25 days long while the calendar uses 365 (with a leap correction every four years). The exact astronomical moment is when the sun crosses the celestial equator heading south; from the UK that is roughly 11:23 am BST on 22 September 2026, but the calendar date is what matters for everyday use.
The equinox marks the astronomical first day of autumn in the Northern Hemisphere. Day and night are not exactly equal: 'equinox' means equal night, but the actual date when day and night last 12 hours each is a few days later (called the equilux), because the sun's disc has a visible diameter and atmospheric refraction bends light around the horizon. From the equinox onwards, days shorten until the [Winter Solstice](/when-is-winter-solstice) in late December, then start lengthening again.
How People Mark the Equinox
The pagan festival Mabon falls on the autumn equinox and traditionally celebrates the second harvest of fruit, grain and the start of the wine pressing season. Stonehenge holds free public access for the equinox sunrise; English Heritage typically opens the inner stone circle from around 4:30 am to 7:30 am for druid and Wiccan ceremonies, with several thousand visitors most years. In Japan, the equinox is a national holiday called Shubun no Hi; families visit graves to honour ancestors. In the southern hemisphere this is the spring equinox, so the same date marks opposite seasons depending on latitude.
Practical effect for UK life: the equinox is when people start commuting home in dusk, which raises road accident rates noticeably (Department for Transport data shows a 6 to 10 percent uplift in pedestrian collisions in the fortnight after the equinox). British Summer Time does not end until the last Sunday of October, so the clocks-back relief comes around five weeks after the equinox itself. If you garden, this is when to plant spring bulbs (daffodils, tulips, crocus) and lift dahlia tubers in colder regions.
Frequently Asked Questions
What date is the autumn equinox 2026?
Tuesday 22 September 2026. In 2027 it shifts to Thursday 23 September, then back to Wednesday 22 September in 2028. The date moves between 22 and 23 September because the calendar year is 365 days while the actual orbital year is 365.25 days; leap years partially correct the drift but a small wobble remains.
Are day and night really equal at the equinox?
Almost but not quite. 'Equinox' means equal night, and the geometric definition (sun directly above the equator) gives 12 hours of daylight in theory. In practice, atmospheric refraction lets us see the sun a few minutes before it geometrically rises and after it sets, and the sun's disc takes time to cross the horizon. The actual 12-hour day is a few days after the equinox, called the equilux.
Is the autumn equinox the first day of autumn?
It is the astronomical first day of autumn in the Northern Hemisphere. The Met Office and most UK climatologists use a different definition: meteorological autumn runs 1 September to 30 November, simply because that gives full calendar months and easier statistics. So depending on which definition you use, autumn starts in early September or in late September.
When does British Summer Time end after the equinox?
BST ends at 2 am on the last Sunday of October every year. In 2026 that is 25 October. In 2027 it is 31 October. The clocks go back one hour, so 2 am becomes 1 am, giving most people an extra hour of sleep that night. From the equinox to the clock change is roughly five weeks; daylight in the UK shrinks by around 4 minutes per day across that window.
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