In reply to duchessofmalfi:
Depends where in Utah--it is a very big state. Much of the climbing is in desert or foothill areas. Typically in such areas,summer climbing in the sun is usually pretty intolerable, while in the shade climbing can be reasonable, though rarely ideal. This covers areas such as the popular canyons on the west side of the Wasatch Mountains--Little and Big Cottonwood (just east of Salt Lake City), American Fork, Logan, etc. The cobble climbing in Maple Canyon a couple of hours south of Salt Lake has similar conditions, though it is a bit more into the mountains so a bit cooler overall--with many sun/shade options as well so is a very reasonable summer objective. I've even climbed further south in the St. George region during the summer, though in general don't recommend it at that time of year. I have no summer experience in the Moab/Canyonlands area but imagine it is much the same. Higher altitude areas, of course, make better summer goals, though areas such as Lone Peak Cirque in the Wasatch above Salt Lake do have quite a lengthy and steep (and hot) approach. One very enjoyable, though not well known, summer area in Utah, is the Mirror Lake area in the Uinta Mountains in the north central part of the state (north of Park City). The area is at 10,000 ft., but very close to a scenic highway and features a selection of quartzite buttresses--mostly single pitch, some sport, some trad in a very pleasant alpine meadow environment. Not too far from the Utah border--only a few hour drive from Salt Lake airport are the City of Rocks/Castle Rock area in southern Idaho and Wild Iris in Wyoming--both popular in summer, as well as the alpine areas of the Wind Rivers and Tetons also in Wyoming.