Many years ago, I rode across Wisconsin from Minneapolis to Saginaw, MI in the first week of October (like in two days). Weather across Wisconsin was beautiful. Clear, high clouds, reliable westerly wind. Cold at night. Into the mid-20s the first night. The day of riding from the Iron Mountain area along the north shore of Lake Michigan was also spectacular. The shore looked like cape Cod and to my left were the colors of autumn Vermont. (I grew up in Boston, so that is my reference base.)
Now the final day was in overcast and light rain. I also saw a touch of rain when I was near Iron Mountain. But that was a small price to pay for a week spent in God's country, the land of cheese and beer (really fresh PBR on tap anywhere for 25 cents/schooner). The Wisconsin countryside was beautiful and the UP with its shore and foliage, wow!
Ben