Weather prognostication may be the most popular Colorado pastime: When will the first snow fall? When will the ice melt? And, of course, when will the leaves change? The annual turning of the aspens, that glorious time when the mountains are awash in gold and crimson, is one of the most beautiful times of year in Colorado, but predicting the peak peeping window can be tough, even for the experts.

Alas, the prime color season will soon be upon us. We’ve got the scoop on when—and where—to spot the Centennial State’s best fall foliage. But first…let’s talk about the science.

How the leaves turn

The process of the leaves “turning” is a matter of chlorophyll—the pigment that causes leaves to turn green—and sugars. When the temperatures get cooler, it sends a signal to trees that winter is coming. As a result, the leaves put down a layer of cells that cause the tree to block chlorophyll from getting back into the leaves. Since it doesn’t rejuvenate, the remaining pigment—those stunning yellows and oranges—is revealed. These are the fall colors we see in the aspens and cottonwoods. Other colors, like reds and purples, are a result of chemical changes within the leaves themselves.

“So what we really want for the perfect color days are abundant sunshine and low temperatures—not cold temperatures and not freezing temperatures,” explained Dr. Dan West, a forest entomologist for the Colorado State Forest Service. “But currently, with the warm temperatures that we’ve got, we’re kind of sitting somewhat delayed by a week, maybe two.”

Predicting peak color season

It’s difficult to predict the exact timing of when the fall foliage will peak, but Matt Makens of FOX31 Denver’s Pinpoint Weather Team is willing to make an educated guess.

“Not seeing much cold on the way, I expect a delay of at least seven to 10 days on the changing colors,” Makens says. “Using the last several years as an average and accounting for the seven to 10-day delay, 2019 puts us into the September 21 to October 1 range for peak colors for areas near Rabbit Ears Pass, the Flat Tops, and Rocky Mountain National Park. The Central Mountains—including areas near the Grand Mesa, Aspen, Gunnison, and Summit County—will likely peak September 24 to October 4. Finally, the southern areas will likely peak in the first two weeks of October. Granted, these are rough approximations, but very reasonable when compared to similar years.”

There you have it—you’re not likely to find a more detailed prediction than that. However, as with everything concerning Mother Nature, you can also expect no shortage of surprises.

Covered in gold

There are plenty of driving routes that will take you through the “gold rush” in the Colorado mountains, like Kebler Pass (home to one of the largest aspen groves in the U.S.—read about it here) that connects Paonia to Crested Butte, Independence Pass between Aspen and Leadville, and the San Juan Skyway, the 236-mile scenic byway that connects Durango, Silverton, Ouray, and Telluride in a spectacular six-hour drive.

(Check out more of Colorado’s best byways)

Photo courtesy of Steamboat Chamber / Shannon Luken.

But to really bask in the golden glory, hit the trails. As Dr. West explained, northern Colorado will see the colors first, with waves peaking from northern to southern latitudes (taking elevation into account as well). Not sure where to go? Here are some of our favorite hikes for experiencing fall colors, moving from the earliest anticipated colors to the latest:

Continental Divide Trail to Fishhook and Lost Lakes | Steamboat
This trek to two blue alpine lakes near Rabbits Ears Pass offers a taste of Colorado’s portion of the 3,100-mile Continental Divide Trail, without the commitment of an overnight backpacking excursion.

Photo by Katie Girtman / Breckenridge Tourism Office.

Boreas Pass | Breckenridge 
Summit County offers a wide variety of leaf-peeping opportunities (Breckenridge’s elevation of 9,600 feet means the leaves often peak earlier than in lower elevation towns). Boreas Pass is a popular spot for hikers, bikers, and cars. But if you want to go it on foot, we recommend the Aspen Alley Trail, an unmarked singletrack path located just past the winter gate, on the right side of the road. This quick, .75-mile jaunt weaves through numerous aspen groves for a spectacular, golden-hued hike.

Maroon Bells | Aspen 
There’s nothing like seeing the colors on Maroon Bells, but rest assured, you’ll be there with plenty of friends. For more low-key sightings, check out the popular American Lake Trail in White River National Forest, or Hunter Creek Valley Loop, which is accessible from downtown Aspen and approachable for almost every level of hiker.

Gem Lake | Rocky Mountain National Park
The journey to this pristine alpine lake is the perfect destination for late fall colors, as the path winds through both pines and aspen groves. Plus, because the trailhead is just outside of RMNP, you can explore the area without the entry fee.

North Twin Cone Peak
Get your fall foliage fix on the beautiful hike up North Twin Cone Peak, which rises above Kenosha Pass. Photo by Logan Abbott

North Twin Cone Peak | Kenosha Pass
Yes, the trails off Kenosha Pass are always packed as the leaves start turning, but if you want to capture a quintessential fall foliage picture and are willing to work for it, this trek up the 12,323-foot North Twin Cone Peak is well worth it.

Looking to stay closer to the city? These Front Range day hikes are perfect for fall.

Don’t forget the southwest

Though most of our fall color tends toward gold, West said that it’s also possible to see reds and purples, especially in the southwestern part of the state.

“If you couple up areas where there’s Gambel oak, you get the oranges and the reds and the gold usually mixed in with some of the green from the ponderosa pine and some of the conifers that we have here and it just makes for this beautiful rainbow,” West says.

There are plenty of opportunities for foliage hikes in Durango—check out the Animas City Mountain Trail. Or, if you want to experience the fall colors in a new way, the Durango & Silverton Narrow Gauge Railroad is offering its annual fall photographer’s special from September 20–21. If you can’t make this train, don’t worry—the fall colors should last well into October.