First Day of Fall Countdown

Fall officially begins at the autumnal equinox in late September, the moment the sun crosses the celestial equator heading south. Day and night are nearly equal, and every day after is a little shorter until the winter solstice.

How many days until First Day of Fall?

First Day of Fall is on Wednesday, September 23, 2026, which is 45 calendar days away. The live countdown above ticks down to the exact moment, to the second.

See where this falls among everything else — the event calendar.

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The story of First Day of Fall

AncientThe Maya built El Castillo at Chichén Itzá so that on the equinox sun, triangular shadows creep down the pyramid's staircase to meet a carved serpent head at the base.

c. 1046 BCEChina's Zhou Dynasty held a formal rite of 'worshipping the moon at the autumn equinox,' a court ritual that later evolved into the Mid-Autumn Festival, fixed by the Song Dynasty (960-1279) to the 15th day of the eighth lunar month.

Silla KingdomKorea's Chuseok, still timed to the full moon nearest the equinox, traces to a month-long weaving contest held under Silla's third king roughly two millennia ago.

325 CEThe Council of Nicaea anchored Easter's date to the vernal equinox, making the equinox central to the Christian calendar — a reckoning so far off by 1582 that Pope Gregory XIII overhauled the calendar to correct it.

1970sThe name 'Mabon' for the Wiccan autumn equinox sabbat was coined around 1970-74 by Aidan Kelly, who borrowed it from a figure in Welsh mythology to give the equinox a Pagan-sounding name.

TodayEquinox does not quite mean equal day and night everywhere: the true equal-daylight date (equilux) falls a few days after the September equinox in the Northern Hemisphere, thanks to atmospheric refraction and the sun's disk width.

What an equinox actually is

Twice a year the sun sits directly above the equator, and Earth's tilt points neither hemisphere toward it. 'Equinox' is Latin for equal night — on this day nearly every place on the planet gets about 12 hours of daylight.

The harvest connection

The full moon nearest the fall equinox is the Harvest Moon, which rises soon after sunset for several evenings in a row — the extra light traditionally let farmers keep bringing in crops after dark.

Quick facts

Fall begins at the autumnal equinox, September 22–23
Day and night are nearly equal everywhere on Earth
The full moon nearest this equinox is the Harvest Moon
Each day now shortens until the winter solstice

Learn more

Wikipedia

First Day of Fall — frequently asked questions

When is First Day of Fall?

First Day of Fall is on Wednesday, September 23, 2026.

How many days until First Day of Fall?

45 calendar days, counting from today: First Day of Fall falls on Wednesday, September 23, 2026. The clock at the top of the page counts down to the exact second.

Updated August 2026 · time-and-space.science

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