Source for maps to help me buy land

I have begun the tiresome task of shopping for a piece of land. I would like to find a source to buy (free is better) maps and statistics to help me, such as - average temperatures, rainfall, tornadoes, wind, snow, etc Does anyone have suggestions on how to go about this?

This can be a bit slow, but it's an excellent resource for getting data on climate, rainfall, and even soil type for locations you are interested in.

http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm