Tell us more: what yeast are you using and what temperature are you fermenting at? What is the lowest temperature you can achieve for lagering (lagering is the storage period)? How is it "getting cold" in Wisconsin when it is 75 degrees in Winnipeg, which is hundreds of miles more northerly than Wisconsin?
FYI when your beer gets to 35 or 40 degrees it is no longer called "fermenting" because the yeast (in general) will be dormant in that temperature range (although I have read about fermentation into the low 40s). And "lagering" is probably best at more like 30 or 32 degrees.
The short answer to your question is "keep it as cold as you can for one week per eight gravity points." i.e. if your Maibock had an OG of 1.064 you would be looking at eight weeks for a recommended lagering time. Few homebrewers have the patience for this, and as I understand it the vast majority of commercial breweries would be nowhere near that length of time. If you can give it a month, you're doing well.
