I have been on the internet and have got the following information on the weather at the different locations. Most are forecasts but you may be interested
Las vegas 34c sunny
Zion canyon 38c Sunny
Bryce Canyon 27c Sunny
grand canyon 30c Sunny
Monument Valley 34c Sunny
Mesa Verde NP 29c Sunny
Salt Lake City 28c Sunny
Jackson 19c could rain and could be cold at night
Yellowstone NP 12-22C??? could rain and cold at night
Sheridan 26c but could rain
Rapid City 29c could rain
As i have already stated most of these temps are projected but it may help with the packing. I look forward to meeting everyone at Las Vegas
Marie