Talk about a weather swing: Folks in the Black Hills area of South Dakota were in shorts and sandals last Monday, enjoying temps in the 80s. By Thursday, local records for both cold and snow were broken as a cold front swept in from the north.
Temps had dropped into the 20s and several inches of snow covered the hills as well as Rapid City and other lower elevations.
Climate skeptics might pounce on the September snow as a rebuttal to global warming, but the early snow that hit parts of South Dakota and other states Thursday and Friday, while uncommon, is not unheard of.
"Even though it is on the early side, snow in September is not unusual for many of the locations which saw it," says NBC News meteorologist Bill Karins. "What was unusual was how widespread it was. Snow was reported in six states over the past three days, including Nebraska."
The mountains of northern Wyoming got the most snow, about 18 inches, while Denver saw snowflakes early Friday as the front moved south, weather.com reported.
In the Black Hills area, "September is a transition month," Alex Calderon, a National Weather Service meteorologist in Rapid City, tells NBC News. So while the snow was "definitely unusual" this early in September, it has happened before and especially in the hills.
Indeed, the previous earliest measurable snowfall for Rapid City, elevation 3,200 feet, was on Sept. 13, 1970, when just under an inch fell.
What was remarkable was by how much Rapid City's snow and cold records were broken. It saw two inches of snow on Thursday, and the temperature never got above 37 degrees — 12 degrees colder than the previous "low maximum" set in 1950.
For Calderon, like the rest of his neighbors, the snow was still a shock to the system.
"I was wearing shorts and sandals and mowing the lawn" on Monday, he says, and a few days later "we're pulling out our winter clothes."
By next week, temps should climb back into the 70s and 80s. And as for the next snowfall?
"We don't see anything on the horizon right now," Calderon says, "but we can't rule out that possibility."