Not sure if you want to be in the Parks right now. Forecasted lows for last night in Yellowstone were between 13 and 17 degrees and it snowed a bit there. However, summer is not over and the weather is supposed to be more like late summer the end of this week and next. If you don't like the weather in Wyoming, just wait for a while, it will change, sometimes for the better and sometimes for the worse. But I love it and that's why we live in Wyoming.