Autumn Dates Table
| Year | Meteorological open | September equinox (UTC) | December solstice (UTC) |
|---|---|---|---|
| 2026 | Sep 1 (Tue) | Sep 23 00:05 UTC | Dec 21 20:50 UTC |
| 2027 | Sep 1 (Wed) | Sep 23 06:02 UTC | Dec 22 02:42 UTC |
| 2028 | Sep 1 (Fri) | Sep 22 11:45 UTC | Dec 21 08:19 UTC |
| 2029 | Sep 1 (Sat) | Sep 22 17:38 UTC | Dec 21 14:14 UTC |
| 2030 | Sep 1 (Sun) | Sep 22 23:27 UTC | Dec 21 20:09 UTC |
| 2031 | Sep 1 (Mon) | Sep 23 05:15 UTC | Dec 22 01:55 UTC |
| 2032 | Sep 1 (Wed) | Sep 22 11:11 UTC | Dec 21 07:56 UTC |
| 2033 | Sep 1 (Thu) | Sep 22 16:51 UTC | Dec 21 13:46 UTC |
| 2034 | Sep 1 (Fri) | Sep 22 22:39 UTC | Dec 21 19:34 UTC |
| 2035 | Sep 1 (Sat) | Sep 23 04:39 UTC | Dec 22 01:31 UTC |
| 2036 | Sep 1 (Mon) | Sep 22 10:23 UTC | Dec 21 07:13 UTC |
Fall has two official starting lines. The meteorological calendar opens it on September 1 and closes it November 30 - the same three months every year, so climate records and forecasts compare like with like. The astronomical calendar waits for the September equinox, which does not sit still: it lands on September 23 in 2026 (at 00:05 UTC, technically the 22nd still in US time zones) and flips between the 22nd and the 23rd across the decade below. The times are official U.S. Naval Observatory figures.
Why two calendars? NOAA's National Centers for Environmental Information put it plainly: meteorological seasons chop the year into tidy quarters that follow the annual temperature cycle, which is what forecasters and statisticians need; astronomical seasons track the tilt of Earth's axis through its orbit, which is what almanacs and sky calendars need. Same season, different bookkeeping - and south of the equator the whole thing flips to March.
How to use
- Type a year between 2026 and 2036 - the counter reads back the days until meteorological fall (September 1) and the days to the equinox.
- Read the table for the exact equinox moment in UTC. US time zones are 4 to 8 hours behind, so the 2026 equinox (00:05 UTC on the 23rd) still lands on the evening of September 22 across the States - one calendar line, two local dates.
- Plan on the 92-day version when paperwork is involved: meteorological fall is always exactly 92 days (September 30, plus October 31, plus November 30), which is why agencies schedule records against it.
Frequently asked questions
Is the first day of fall always September 22?
Not even in UTC. The 2026 equinox lands on September 23 at 00:05 UTC, and the date flips between the 22nd and the 23rd across this table while the clock time drifts about six hours later each year. Meteorological fall sidesteps the astronomy and starts September 1, every year - which is why these dates hold still.
Isn't the autumn equinox exactly 12 hours of daylight?
Almost, never quite - and autumn has its own twist. The sun's disk plus atmospheric refraction keep daylight a few minutes longer than 12 hours at mid-latitudes, so the true 12-12 split falls a few days AFTER the September equinox (in spring it comes before). Most fall pages skip that detail.
When does fall start in Australia?
It flips. South of the equator, meteorological fall runs March 1 to May 31, and the astronomical season opens with the March equinox. A September beach day in Sydney is a spring day - the definitions follow the hemisphere, not the month.
Which season is the longest?
Northern summer, by a clear margin: about 93.6 days, because Earth crawls through the farthest part of its orbit in July. Astronomical fall runs about 89.9 days - second shortest after winter's roughly 89 - and you can read both straight off the table, equinox to December solstice.