Se utah in July

Thanks a lot knew I would get some good information. Hadn't thought about a 12 volt fan or the wet towels will add to my list of things to buy and do.

Can be variable. We were at Canyonlands NP in June, went hiking before noon, huddled in the shade in the afternoons; it usually cooled off in the evening but takes a while because of the heat in the rocks. I recall a couple of hot nights and one really bad sand/windstorm.

Try to position your trailer so it's in the shade in the afternoon.

Also might dry an evaporative cooler with a small fan if lots of water is available. The air's so dry there, water easily evaporates and cools down the surroundings. Maybe just a bunch of towels soaked in water and hung up would help.

we just got back mid- June. It was hot during the day, but a little shade makes a huge difference in the afternoon. We stayed at Goose Island, right on the Colorado River, NE of moab. There is a HUGE cliff that shades the campground from about 4 on. It ain't cool but it's bearable at night with a little 12v fan. If you get a chance and have a vehicle that can go offroad, don't miss Schafer Trail

Yes, it cools after dark. I recall camping at Devil's Garden (no hookups) in Arches NP in August when it was well over 100 late afternoon/early evening, but we had no trouble sleeping as it cooled. I'd recommend a little 12-volt circulating van to move the air around.

Hey me too but I'll be starting in Moab and working my way down to Zion.
Yea, it will cool down to about 90 ;). Given the high elevation it does cool down considerably after sunset and is quite comfortable IMHO.

Last time there (yrs ago) I camped off grid and put more miles on dirt than pavement. No issues with heat or the few people I ran across, had a blast. Be aware of sudden thunderstorms and flash floods as August is monsoon season. Don't camp in a wash. I suffered from hyperthermia due to miscalculation of water on one slot canyon hike. Carry lots of water.