That is the Great Plains for you!. I was in Rapid City, SD about 7 years ago around August 1st. It was around 85 F when I arrived about 6 PM local time. I stopped at the Walmart next to I-90 to fill up my gas tank. I could see a storm to the northwest as I was filling the tank and the wind began to pick up. It looked liked something from an Indiana Jones movie. It arrived about 20 minutes later after I got to my daughters residence for the summer. When we walked out to go to dinner, it was about 60 F but with little wind. It was a 25 F drop in 20 minutes by that wind storm with no rain!
That summer it hit 110 F in Rapid City, tying the record high temperature for ANY date. My daughter was glad that her dorm had AC, which was the first question that I asked her when she told me that she had a summer job at the South Dakota School of Mines and Technology. Before we left for Milwaukee, we walked the 2 doors down to the school museum. She had no idea how cool it was, but her mother and I had been there about 30 years before and I went as a kid in 1967. I was disappointed that they didn't have the dinosaur that was pregnant with twins anymore. I have never seen that in any other museum in the world. They sell off items to keep the museum going. Sue the dinosaur was another one. She went to the Field Museum in Chicago.