If you're not interested in outdoor activities such as hiking, biking, skiing, etc., you'd probably find Cedar City rather dull. The setting is beautiful. And the climate is decent, if you like 4 seasons that is. However, the town itself is not particularly exciting. With Southern Utah University there, you'll have at least some taste of culture and progressive thinking. However, like most every American town of it's size, there is an aversion to zoning and therefore a proliferation of ugly sprawl. Building huge chain retailers on the outskirsts of town, surrounded by a sea of asphalt, while the once thriving downtown area deteriorates. Not so charming.
Another major*/- factor to consider is Mormonism. If you yourselves are Mormons then no problem. If you're not, you might feel the culture rather stifling. The Mormons are generally very nice people, but some of their religious beliefs are downright bizarre, and they run the show in Utah, especially rural Utah. They also tend to keep to themselves. On the plus side, of course, they won't declare a fatwa and cut off my head for saying things like this. Plus, they produce a fine law abiding citizenry, so that the crime rate in a place like Cedar City would be very low.
As far as weather, check this link for averages:
You'll get a much wider range of temperatures than you get in England. The elevation (5800 ft.) is high enough that the summer temperatures are actually pretty moderate, so A/C would be overkill, with an evaporative cooler being adequate. It can snow down there anytime from October through April, but the climate will generally be much drier and sunnier than England.