Morton Arboretum tracks the impact climate change is having on fall leaves changing color

If you have been thinking the fall leaves aren't changing colors like they usually do this year, you're right. The shades of orange, red, yellow, green and brown we're used to seeing by late October are being impacted by climate change.

Those colors reflect the changing of the season, but they also reflect our changing weather.

"It's such a different year," said Christy Rollinson, forest ecologist and senior scientist at the Morton Arboretum. "I've been pins and needles, and having to go around and check out what's going on with the fall colors."

Rollinson studies how changing weather is impacting the seasonal change. The warm October the Chicago area has experienced has made an impact. The leaves are changing later this year and the repercussions are not just aesthetic.

"What is in the leaves is so valuable. So when a leaf freezes, it's like putting a water bottle in your freezer and it explodes," Rollinson explains.

Climate Central, a nonprofit of leading scientists studying climate change, has tracked a shift in fall colors across the country, including early and late peaks. Sometimes that means slater and shorter color seasons.

"What I'm trying to figure out is how much of it is impacting the actual color aspect of color," Rollinson said. "How much yellow we see versus how much red we see. That's all affected by the trees' biology."

The changes also aren't unique to fall. The outlook for 2026-2027 winter, with a potentially historically strong El Nino expected, means we could see warmer temperatures and less snow.

Another warmer season will again likely impact what's in our backyards and spaces like the Morton Arboretum.

"We are going to be paying attention next spring to, oh, do we need to watch out for pests and pathogens that aren't normally as big of a problem," said Rollinson.