Skip to Content
/ Articles / Environment /

PA’s Warm Fall, Rainy Summer Might Be Impacting Autumn Foliage

by Emily Scott, Keystone State News Connection

Oct 15, 2021
Vivid Autumn foliage is reflected in still lake in the golden hour, with periwinkle sky. Image created at Nockamixon State Park in Bucks County, Pennsylvania. DSLR image at low ISO captures magnificent fall color warmth in a horizontal format late in the day.

October is usually the best time of year to see the bright, changing leaf colors that ring in autumn in Pennsylvania, but researchers say the wet, warm weather of the last few months may result in muted fall foliage.

When the days get shorter and the temperature drops, chlorophyll, which creates leaves’ green pigment, breaks down, while anthocyanin, which causes the red coloring, is produced. The ideal conditions for this are moist summers and drier fall seasons.

Pennsylvania saw one of the wettest summers on record this year and an unseasonably warm fall so far, which has led to a delay in the changing leaf colors.

Marc Abrams, professor of forest ecology and tree physiology at Penn State University, said when fall foliage is late, it can lead to a shorter peak period for viewing.

“We might have a sudden frost come about at any time, and when that hits the green or just slightly changing leaves, it will turn them brown rather quickly,” Abrams explained. “All those things could either truncate or be a further negative factor for fall colors this year.”

This summer was the seventh hottest and 11th wettest on record for Pennsylvania, according to the National Oceanic and Atmospheric Administration. Abrams pointed out in central Pennsylvania, peak coloration is occurring about half a week later than it did about 40 years ago.

Among the types of trees in Pennsylvania appearing most impacted by the extreme weather are sugar and red maple, both major color-producing species, suffering from a leaf fungus. Even though the foliage has been disappointing so far, Abrams is holding out hope colder temperatures in the next few weeks will create stunning landscape views.

“Fall color can be really resilient and actually overcome a lot of these negative factors,” Abrams noted. “I still encourage people to get out there. Keep an eye on when things are starting to change in your area and take nice drives into wooded areas and try to seek out these really good colors.”

The Department of Conservation and Natural Resources also offers weekly statewide reports showing where and when Pennsylvania leaves are at their peak.

We need your support!

Your contribution makes community media possible.

A donation of any size to your nonprofit media organization supports the future of media access in our community - the things you love, and the places you care about, by the people you know.

Live Streaming