It’s a week past the autumn equinox, and the first snows have fallen in the Rockies and the mountain peaks of New England. But in Hazen, N.D., the mercury soared to the century mark Tuesday afternoon.
The scorching temperature comes after a tie for the hottest summer on record in the Lower 48 states. It was first reported by Maximiliano Herrera, a climatologist who tracks world weather extremes.
Hazen is a small city of just over 2,400 people about 50 miles northwest of Bismarck. It’s in a hilly location, sitting at an elevation of 1,800 feet.
“A temp of 100F one week after the autumn equinox is an absolute insanity,” Herrera tweeted.
Hazen was among numerous locations that endured record-breaking heat in the northern Plains on Tuesday. Bismarck rose to 98 degrees, while Dickinson, N.D., about 60 miles southwest of Hazen, also hit 100. In South Dakota, Rapid City and Aberdeen both soared to 94, setting records for Sept. 28.
Temperatures across the border into Canada climbed as high as 93 degrees.
Exceptional #heat in southern #Canada with up to 34.1°C in Yellow Grass [Tmin 4.0°C!], 33.9°C in Bratt's Lake, 33.8°C in Weyburn, 33.3°C in #Regina, 33.0°C in Indian Head, 32.8°C in Assiniboia, #Saskatchewan and 32.5°C in Melita, 32.4°C in Swan River, #Manitoba.#SKstorm #MBstorm pic.twitter.com/QTXt7IHTMF— Thierry Goose (@ThierryGooseBC) September 29, 2021
Amid the hot, dry and breezy conditions, the National Weather Service in Bismarck warned of a “critical” fire danger and issued a red-flag warning for dangerous fire weather.
The exceptional autumn heat wave occurred due to a bulge in the jet stream over central North America and a strong high-pressure zone or heat dome underneath it. Some of the highest temperatures in the Northern Hemisphere, compared to normal, were parked over the region.
Average high temperatures in interior North Dakota in late September are in the 60s, meaning the actual readings deviated about 30 degrees from the norm.
On Wednesday, a cold front pushed the unseasonably hot weather to the east, and temperatures dropped 30 to 40 degrees. Bismarck reported rainy weather and temperatures near 60 degrees late Wednesday afternoon.
The core of the heat had pushed into the Upper Midwest. Minneapolis and Madison saw highs in the 80s.
Much of North America has become accustomed to exceptional heat in recent years amid rising temperatures due to human-caused climate change. Extraordinarily high temperatures have expanded the duration of summerlike conditions, while the colder seasons have shortened.
This month, Denver hit 99 degrees Sept. 10, its highest temperature recorded so late in the season. That same week, Death Valley in California reached 122 degrees, the highest temperature observed so late in the year anywhere on the planet.
This article originally stated that news of this 100-degree reading was first noted by Guy Walton, a meteorologist retired from The Weather Channel. Walton contacted us to let us know Maximiliano Herrera first posted the information. This story has been updated.