Wyoming Simmering In September With Temps 20 Degrees Above Average

It’s officially fall in the Cowboy State, but it still feels like summer. Daytime highs are reaching into the 80s and 90s this week, coming close to or breaking record highs for late September.

With the heat and peak fall colors coming at the same time, Wyomingites will want to see their state at its best. It’s not going to stay in midsummer form for long.

“This is your peak opportunity,” said Cowboy State Daily meteorologist Don Day. “We’ve got warm September weather, and the colors are going to be peaking, so this would be a great weekend to get out and enjoy it.”

Simmering But Unsurprising

The National Weather Service reports it could be as high as 87 in Cheyenne on Thursday, close to the record-high of 89 degrees for Sept. 26. Saturday’s projected high of 89 degrees would tie the record and could surpass it if it gets hot enough. Average for this time of year in Cheyenne is 68.

Gillette might be the hottest spot in Wyoming this week, espected to hit 92 degrees Thursday. That’s 23 degrees warmer than average and close to that city’s record high of 93.

Casper should hit 91 on Wednesday, 20 degrees warmer than average but shy of the record of 98 for Sept. 25. Saturday’s daytime high could reach 89 degrees, 17 degrees above average but still shy of the record-high 91.

Cody will flirt with its record highs throughout the week and the weekend, with highs in the mid-80s for the duration. That’s around 20 degrees warmer than average, and sometimes even higher.

Meanwhile, Rock Springs will come close to breaking multiple daytime record highs, with temperatures in the low 80s into the weekend, 12-15 degrees above average.

Day wasn’t surprised that it’s 20 degrees warmer than average across most of Wyoming. It correlates with his long-range forecast for the season, which called for a warmer, dryer September in the Cowboy State.

“Having warm periods like this is not unusual in late September,” he said. “Is it above normal? Yes, without a doubt. And this warm, dry weather is going to go on for a bit.”

Peak Color

Wyoming’s weather has been great for the last few weeks and should stay warm and mild for the next week. That first weekend of autumn might be the best weekend to get out and enjoy it.

Fall colors are reaching their peak across Wyoming. This weekend should be the peak for the high-elevation aspen groves in Yellowstone and Grand Teton national parks, while cottonwoods and other low-elevation trees should start turning if they haven’t already.

There will be plenty of peak fall colors to see in October. However, Day said September’s trends suggest this upcoming weekend might be the best of the season for a Wyoming fall experience.

“The combination of really vibrant colors and warm weather is really good,” he said. “This is the weekend for the best fall experience.”

‘The Dam Breaking’

It might be nice and warm now, but there’s always a change on the horizon.

Day said “the pendulum” of Wyoming’s weather will soon swing the opposite way.

“When you have really nice weather at this time of year, the opposite is happening upstream,” he said. “Eventually, we'll run out of luck and the pendulum will go the other way. I call it ‘the dam breaking.’”

“The dam breaking” in Wyoming means cooler temperatures and the first significant snowfalls of the season. Several regions of the state have already reported their first frost, and despite the 80-degree daytime highs this week, overnight temperatures are still nearly freezing.

Day doesn’t expect the dam to break until October, so there’s still plenty of time to savor September.

“I always say Mother Nature is a great equalizer,” he said. “We have a great stretch of weather right now, but we'll probably see it getting colder and more chances for a fall pattern arrive between October 5 and 10.”

The Most Wonderful Time Of The Year

The moral of this weather story is to savor the summery September while it lasts. It might be unseasonably warm and dry, making it the ideal weekend to experience fall in Wyoming.

“This is my favorite time of year,” Day said. “The days are warm, sunny and dry, and the nights are nice and cool. It makes for great weather for the next five or six days.”

The recent snowstorm that closed the Beartooth Highway is a sign of the pendulum swing to come, but Day doesn’t think anyone should look too much into it. The last days of September will be “benign,” with plenty of opportunities for warmth and color.

“As we get into October and November, we'll probably see a stretch of weather that's opposite of what it is right now,” he said. “I talked to some folks from the Bighorns, the Green River lakes and areas up there by Pinedale, and they said the colors were just phenomenal. This is the weekend to feel and see fall in Wyoming.”

Andrew Rossi can be reached at arossi@cowboystatedaily.com.