Can you swim in Wisconsin in winter? In December water temperature throughout Wisconsin is not yet warm enough for swimming and does not exceed 68°F. Based on average water temperature observations over the past ten years, the warmest water temperature in Wisconsin in December was 41.4°F (in Simmons Island Beach), and the coldest 35.6°F (in Lake Winnebago). To find out the sea temperature today and in the coming days, go to Current sea temperature in Wisconsin
Wisconsin cities and resorts with the values of the average water temperature in December in recent years.
For more detailed information about water temperature, surf forecast, weather and time of sunrise and sunset in any specific area of your interest, just click on a city name. For ease of search, all places are also grouped by the first letter of the name.
To find out what the water temperature was in Wisconsin any day over a period of the last ten years, select the month