As you may have gathered, I keep a fairly good eye on the US weather. Mostly it's because my preferred weather site, "Weather Underground," has a beautiful, color map of the entire US by temperature (rest of the world available too). So it's very easy to see extremes.
I don't believe I've ever seen this before: a state where every reporting station in the entire state is over 100 degrees F. These readings were as of approximately 6:10 p.m., local time, on Monday. The adjacent states of Kansas and Arkansas are about the same.