Fall Foliage Peak Map: When Autumn Leaves Are Best In PA

PENNSYLVANIA — It’s a good time to begin planning road trips to see one of nature’s greatest shows: the fall foliage peak, when leaves change color to blazing reds, vibrant oranges and sunny yellows. When will that happen in Pennsylvania?

You can’t know precisely, but there’s a handy tool to help you plan excursions when fall foliage should be at its most spectacular.

The Fall Foliage Prediction Map, found on the Smoky Mountain National Park website, includes predictions not just for the Smokies, which rise above the Tennessee-North Carolina border, but for all 50 states.

In Pennylvania, fall colors are expected to peak around the week of Oct. 19. Our state offers some stunning fall vistas, including several in state parks. Here are some of the best for foliage viewing, according to Visit PA:

• Big Pocono State Park
• Gettysburg National Military Park
• Washington Crossing Historic Park
• Pine Creek Gorge

If you’re planning a trip somewhere else, the Fall Foliage Prediction Map can help you pinpoint the best dates for a visit.

"The predictive fall leaf map helps potential travelers, photographers and leaf peepers determine the precise future date that the leaves will peak in each area of the continental United States. By utilizing the date selector at the bottom of the map, the user can visually understand how fall will progress over a region,” data scientist Wes Melton, the website’s chief technical officer, said in a statement.

“We believe this interactive tool will enable travelers to take more meaningful fall vacations, capture beautiful fall photos and enjoy the natural beauty of autumn,” he said. “Our nationwide fall foliage prediction map is unique — it is one of the only fall leaf tools that provides accurate predictions for the entire continental United States."

The major factors that determine the fall foliage peak are sunlight, precipitation, soil moisture and temperature.

“Nothing is 100 percent accurate,” David Angotti, the cofounder of the website told Patch, but the tool “gets pretty darned close.”

Of course, “we can have a brilliant fall, and Mother Nature can come in with a wind storm and rip those leaves off in minutes,” Angotti said.

The website refines its predictive algorithm every year, using hundreds of thousands of data points from private and government sources, including historical and forecasted temperatures and precipitation data from the National Oceanic and Atmospheric Administration, historical leaf peak trends and peak observation trends.

New maps are created from scratch every year using new data that reflects the drastic year-to-year changes, and the prediction becomes more accurate as the foliage peak nears, Melton said.

Where To Find The Best Fall Color

Angotti and his team monetize the Fall Foliage Prediction Map with Smoky Mountain cabin rentals.

“At the time we started, we had a lot of people asking about fall color in the Smoky Mountains,” Angotti said. “We didn’t want to give people bad advice, so we started talking with a meteorologist. The first year was pretty accurate and was very well received, and people were asking, ‘Are you going to do it again?’”

That was six years ago.

“It’s our M.O. now,” Angotti said. “We don’t have a choice.”

He admits some “bias that Tennessee has some of the best leaves in the country.”

“I honestly do believe that,” Angotti said, “but you’ll also find good color in the Blue Ridge Mountains; up in the Northeast corridor, especially Vermont and even into Virginia; the Poconos in Pennsylvania; the Colorado aspen trees; and in a lot of different areas of the country.”

What Causes The Different Colors

You probably remember from science class that the color change all starts with photosynthesis. Leaves constantly churn out chlorophyll — a key component in a plant’s ability to turn sunlight into the glucose it needs to stay healthy — from spring through early fall. Those cells saturate the leaves, making them appear green to the human eye.

But leaves aren’t green at all. Autumn is the time for leaves’ big reveal: their true color, unveiled as chlorophyll production grinds to a halt. The colors in fall’s breathtaking tapestry are influenced by other compounds, according to the national park’s website.

Beta carotene, the same pigment that makes carrots orange, reflects the yellow and red light from the sun and gives leaves an orange hue.

The production of anthocyanin, which gives leaves their vivid red color, ramps up in the fall, protecting and prolonging the leaf’s life on a tree throughout autumn.

And those yellows that make you feel as if you’re walking in a ray of sunshine?

They’re produced by flavonol, which is part of the flavonoid protein family. It’s always present in leaves, but doesn’t show itself until chlorophyll production begins to slow.