This is a good batch or information I found when contenplating a move to Wisconsin. Have a look at it and it will answer a bunch of your questions.
http://hosted.ap.org/dynamic/fronts/...p;SECTION=HOME
I don't know if the link will work but just get on koin's website and look for census information. A big part of our not moving was what I found out about the weather. We were willing to brave the cold in the winter, but when I saw the summer rain fall and temperatures, Not a chance. At least in Helena you have great summer weather after the cold winters.