On the first day of autumn, the hills around Warren County were mostly green.

But that could change quickly.

“It’s probably going to be an early season,” according to DCNR Cornplanter District Forester Cecile Stelter. “Cooler temperatures this weekend combined with this warm sunny week with cool evenings, that’s really going to bring on some color.”

The peak foliage will start early and may not last long. “The dry hot weather that we had in the summer is probably going to make the season a little shorter,” she said.

The peak of the season in the area should start around Oct. 10 and last through Oct. 20.

“We expect that we’ll peak around Columbus Day,” Allegheny National Forest Public Affairs Officer Ruth Sutton said.

Stelter said she expects the height of the peak to fall from Oct. 15 through 17.

Some leaves will still be green then – which is an advantage because it provides a broader range of color, she said. “That lets the colors offset.”

With 134 native species of trees and some 60 more introduced, the state has a mix of colors and timing for the fall season, she said. “All of those have different color variations. That’s what makes Pennsylvania so beautiful in terms of fall foliage.”

It’s about location. “We’re just at the right place in the world to have the trees that we have,” Sutton said.

Much of the summer has been filled with hot days and warm nights. That’s not perfect for producing vibrant foliage. Ideal conditions are “warmer sunny days, cool nights, no frost,” Stelter said.

While this fall season may not be the best and brightest ever in northwest Pennsylvania, the region has an edge over much of the rest of the state.

“Northwest Pennsylvania actually got more precipitation than a lot of the areas in the state,” Stelter said. “I expect that our fall foliage is going to be brighter than a lot of areas around the state. The Northwest is definitely one of the places to visit for fall foliage.”

Visitors working to plan a trip to the area to see the leaves can check the DCNR Bureau of Forestry website’s weekly foliage reports, she said. “People who are traveling can go on our website, see what our percentage of color is, what’s predicted, and any activities that might be going on in the region related to fall foliage.”

The U.S. Forest Service fall foliage hotline will be activated soon, Sutton said. The website will be updated weekly and show conditions nationwide.

The Allegheny National Forest website includes photos of some of the most picturesque spots in the forest. Right now, the link only has two – one of changing grass colors at Beaver Meadows in Clarion County – but more will be added as the season progresses, Sutton said. “There’ll be a slideshow eventually.”

Sutton said she is looking forward to the season and “how beautiful Rimrock is going to be and the reservoir. We can’t wait for those colors to change.”