Herbiesrig,
These are two good parks are in the St George area.
Willowind in Hurricane is a good long term park.
http://www.willowindrvpark.net/
Zion River Resort in Virgin is nice, maybe a little pricey.
http://www.zionriverresort.com/
I agree with Chopper, we have never found a park we really like right in St George. Although St George itself is a great city.
The RV park snow birds flock to, right in SG is right off I-15. I forget the name. Too noisy for me.
You can also check out Temple View RV Park. I didn't really care for it. Most spots are very small.
Hope this link works. It's for year round St George climate data.
http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?ut7516
Southern Utah has very mild winters by Michigan standards. Trace