2020 Fall Foliage Peak Map: When Leaves Are Best In Illinois

Shannon Antinori
·4 min read

ILLINOIS — The first day of fall is still weeks away, but the autumnal equinox isn’t the best measure of when foliage will turn to blazing reds, vibrant oranges and sunny yellows in Illinois.

No predictive tool is 100 percent accurate, but using the newly released interactive “2020 Fall Foliage Prediction Map” can give you a pretty good shot at seeing autumn leaves at the peak of their splendor.

In northern Illinois, the week of Oct. 19 looks good for a trip into the great outdoors, while the rest of the state will be at near peak for fall foliage and will hit their peak the week of Oct. 26.

Developed as a tool to help vacationers book lodging and other accommodations in the Smoky Mountains, which rise above the Tennessee-North Carolina border, the Fall Foliage Prediction Map from SmokyMountains.com provides peak leaf change predictions for the entire continental United States.

To use the map, simply slide the scale to the right to see when leaves will peak in your state. Zero in on your county, and you’ll be able to decide whether it’s best to plan a northern, southern, eastern or western route.

Illinois has some great vistas to view fall leaves — just be sure to visit the website before you head out for the latest coronavirus social distancing guidelines. Here are a few prime spots:

The major factors that determine the fall foliage peak are sunlight, precipitation, soil moisture and temperature. The map takes in 50,000 predictive data sets, then churns out a county-by-county analysis of when the fall peak will occur, according to SmokyMountains.com co-founder David Angotti, an expert on statistics.

The data comes from a variety of sources including historical precipitation, National Oceanic and Atmospheric Administration precipitation forecasts, elevation, actual temperatures, temperature forecasts and average daylight exposure to develop each county’s fall baseline date.

Angotti said improvements in algorithms used in the map combined with meteorological data sources have improved the reliability of the map, though he cautioned accurate meteorological predictions are “somewhat elusive and never 100 percent accurate.”

“However, the good news is that the combination of nearly a decade of experience combined with great meteorological data sources ensures we achieve a higher accuracy over time,” he said in a news release.

A new map is created every year due to dramatic changes from one year to the next, the release said.

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 thrive — 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.

This article originally appeared on the Across Illinois Patch