Rapid City and Weather

When I told folks in DC that I was moving to Rapid City, they told me how cold it was going to be. I'd then explain to them, that no, Rapid City is in a little Banana Belt and that the weather varies considerably. So it may be cold for a few days, but then the sun would shine and the snow would melt. The folks didn't believe me. To them, I say, Hah!

Highs over the last three weeks:
Saturday, September 26: 83 degrees Fahrenheit
Saturday, October 3: 50 degrees
Saturday, October 10: 20 degrees (and snow)
Saturday, October 17: 71 degrees

Weird.