Extreme temperature swings won't bring much change to fall foliage forecast, expert says

Justin Udo
October 02, 2019 - 3:19 pm
Fall foliage seen in Hawk Mountain Sanctuary, Albany Township, Berks County.

KYW Newsradio


PHILADELPHIA (KYW Newsradio) — The Delaware Valley is seeing 45 degree swings in temperatures in just two days, and there's been concern the swings could have a negative impact on the fall foliage so many people like to view.

Ninety degree temperatures are unusual for this time of year, but experts say they are not harmful and will not do much to change the fall foliage forecast for the region.

"Temperatures over the next week of highs in the 60s and 70s, and then cool temperatures at night with sunny days is really ideal for fall color," explained Anthony Aiello, curator and director of horticulture at the Morris Arboretum.

It's not the heat we should be worried about, Aiello said, as drier weather is more of a concern.

"Because it's been so dry, a lot of the plants are losing their leaves already. But the good news is we had a very wet summer, and so a lot of the bigger trees have been fully hydrated, grown well," he said. 

And the extra sun the trees are getting is a good thing.

"What we don't want are long periods of cloudy days because that really doesn't allow the trees to develop good color," he explained. 

If the region doesn't get a few more days of wet weather, we may see a more muted fall, where trees just lose their leaves without changing color. As of now, Aiello said, most trees are on schedule to color up within the next few weeks.

"The last half of October is really the great time to get out and see fall color," he said. 


If it seems like those changing leaves are taking a little longer to come to Philly, just be patient.

"The city is a little bit warmer. Things are always a little bit delayed compared to here even in Chestnut Hill, so there's maybe a couple differences in terms of fall color even there," he added. 

In addition to the Morris Arboretum, Kelly drive, Martin Luther King Jr. Drive and Forbidden Drive make great places to enjoy the view in Philadelphia.

For more information on when you can expect to see to the best foliage from different kinds of trees across Pennsylvania, check out the Department of Conservation and Natural Resources' fall foliage reports.