The water temps in Wisconsin are fully controlled by many factors of the weather. For the ‘seasonal’ paddler, the ideal time of the year to be on the water runs between May and September. Normally, smaller lakes and rivers will range between 50 and 80 degrees during this time of year. Lake Michigan is a bit lower (and changes daily) usually between 40 and mid-upper 60’s. A properly dressed and experienced paddler can extend this time.