When is the first day of fall in Pennsylvania? When foliage starts to change
Cumru Twp, PA - October 27: Orange and red autumn fall foliage leaves on trees along Philadelphia Ave in Cumru Township change colors Wednesday morning October 27, 2021. (Photo by Ben Hasty/MediaNews Group/Reading Eagle via Getty Images)
PENNSYLVANIA - Fall officially arrives in Pennsylvania on Sept. 22, but the first signs of the season — cooler nights, changing leaves and packed apple orchards — will not arrive everywhere at the same time.
When does fall begin in Pennsylvania?
What we know:
Astronomical fall begins at 8:05 p.m. ET on Sept. 22, the moment of the autumnal equinox.
That is different from meteorological fall, which begins Sept. 1 and includes September, October and November.
The equinox marks the moment when the sun crosses Earth’s equator heading south, bringing autumn to the Northern Hemisphere. NASA explains the 2026 equinox will occur at 12:05 a.m. UTC on Sept. 23, or 8:05 p.m. ET on Sept. 22.
When will leaves start changing in Pennsylvania?
There is no single statewide date for peak fall color.
Pennsylvania’s Department of Conservation and Natural Resources releases weekly foliage reports and an interactive map during the season. The first reports were released Sept. 25 in 2025 and Sept. 26 in 2024, a useful guide for when widespread color typically starts being tracked.
The timing varies by region, elevation, tree species and weather. Northern and higher-elevation areas generally begin to show color before the rest of the state, while southeastern Pennsylvania often follows later.
DCNR cautions that no two foliage seasons — or even two locations — are exactly alike. A late spring, a dry summer and warm fall weather can all affect when leaves begin changing and how long the color lasts.
Why do leaves change color?
As days get shorter and sunlight weakens, trees begin shutting down the process that keeps leaves green.
The green chlorophyll fades, revealing yellow and orange pigments that were already in the leaf. Reds and purples develop later as sugars and other chemicals change inside the leaf.
DCNR says the brightest foliage usually follows dry late-summer conditions, sunny fall days and cool nights. Early frost or strong wind can cut the color season short. Read DCNR’s foliage explainer and follow its weekly reports here.
What is there to look forward to this fall?
The coming months bring Pennsylvania’s favorite seasonal traditions: apple picking, pumpkin patches, corn mazes, fall festivals, football weekends and Halloween events.
For leaf peepers, the best plan is to watch DCNR’s weekly foliage map rather than locking in a trip too far in advance. The reports include regional updates, photos and tips from foresters on where color is developing.
What's next:
DCNR’s first weekly foliage report of the 2026 season has not yet been released. Check back as the fall color season gets closer for the latest Pennsylvania updates.
The Source: This article was written using information from NASA and the Pennsylvania Department of Conservation and Natural Resources.