🍂 First Day of Fall Countdown
September 22, 2026
About the First Day of Fall
The first day of fall, the autumnal equinox, marks when the sun crosses the celestial equator heading south. Day and night are approximately equal in length, and temperatures begin to cool in the Northern Hemisphere. In 2026, the fall equinox occurs on September 22. The season is associated with harvest festivals, changing leaf colors, pumpkin picking, and the approach of Halloween and Thanksgiving.
Frequently Asked Questions
When does fall officially start?
Astronomical fall begins at the autumnal equinox, which typically falls on September 22 or 23 in the Northern Hemisphere. Meteorological fall — used by weather services for consistency — begins on September 1 and runs through November 30. In 2026, the autumnal equinox falls on September 22.
Why do leaves change color in fall?
As days shorten and temperatures drop in autumn, deciduous trees begin shutting down chlorophyll production in preparation for winter dormancy. Chlorophyll is the green pigment that gives leaves their color during the growing season; as it breaks down, the yellow and orange carotenoid pigments that were present all along (but masked by green) become visible. Some trees, like maples and oaks, also produce red and purple anthocyanins during leaf senescence, producing the most brilliant fall colors.
Where is the best fall foliage in the US?
New England is the most famous destination for fall foliage — Vermont, New Hampshire, and Maine typically reach peak color in early to mid-October. The Great Smoky Mountains of Tennessee and North Carolina offer spectacular fall color in mid-October. The Adirondacks and Catskills in New York, and the Upper Peninsula of Michigan, are also renowned. Color timing varies by elevation and latitude — higher elevations and more northern latitudes peak earlier.
What is the meteorological vs. astronomical definition of fall?
Meteorological autumn runs September 1 through November 30 — a fixed three-month period used for temperature statistics and weather data consistency. Astronomical autumn begins at the autumnal equinox (around September 22) and ends at the winter solstice (around December 21). Most people experience the season as running from Labor Day weekend through Thanksgiving, regardless of either scientific definition.