I was in Cody Wyoming when we went to Yellowstone. I was surprised how chilly it was there. It was like the beginning of August and the temperature was maybe 40 degrees overnight, and jacket weather duing the day. Other parts of Wyoming had been quite warm. I am not sure what the elevation is there, but defintely a chilly place. I loved that trip, I would love to take it again. Of course we almost got blown away by a tornado in SD...We took shelter in the car, but we were using a tent at the time with an air mattress and the air mattress got blown out of the tent, and ended up on the other side of campground!