Lake Keesus — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Keesus, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Keesus today is 21.2°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 68°F (20°C) to 74°F (23°C). The water is warm and pleasant for swimming, and in this range, one can stay in the water for extended periods without the risk of hypothermia. This is the ideal temperature for relaxation, swimming, and water sports. Families with children, as well as outdoor enthusiasts, will enjoy swimming and time spent in the water. For most people, this is the optimal temperature for a comfortable beach experience. It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.
Water Temperature Chart Over the Last 30 Days
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| JUN 2 | 19.1°C | 18.6°C | |
| JUN 3 | 19.8°C | 18.6°C | |
| JUN 4 | 19.8°C | 18.6°C | |
| JUN 5 | 20.1°C | 18.6°C | |
| JUN 6 | 20.1°C | 18.6°C | |
| JUN 7 | 20.6°C | 18.6°C | |
| JUN 8 | 20.8°C | 18.6°C | |
| JUN 10 | 18.6°C | 21.1°C | |
| JUN 11 | 18.6°C | 20.9°C | |
| JUN 12 | 18.6°C | 20.8°C | |
| JUN 13 | 18.6°C | 20.7°C | |
| JUN 14 | 18.6°C | 20.6°C | |
| JUN 15 | 18.6°C | 20.4°C | |
| JUN 16 | 18.6°C | 20.3°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.
Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 0°C | 2°C | 4°C |
| February | 1°C | 4°C | 6°C |
| March | 1°C | 5°C | 8°C |
| April | 5°C | 9°C | 13°C |
| May | 7°C | 13°C | 19°C |
| June | 16°C | 19°C | 22°C |
| July | 20°C | 25°C | 29°C |
| August | 22°C | 25°C | 27°C |
| September | 18°C | 20°C | 22°C |
| October | 13°C | 17°C | 20°C |
| November | 3°C | 9°C | 15°C |
| December | 0°C | 3°C | 6°C |
Lake Keesus: Water Temperature by Location
Lake Keesus: Weather Forecast
June 9
June 10
June 11
June 12
Location & Local Information
Lake Keesus, a medium-sized inland lake in Waukesha County, typically follows the seasonal temperature patterns of southern Wisconsin lakes. In summer the surface water commonly warms to roughly 70–80°F (21–27°C) and can reach the low 80s°F (27–28°C) on particularly warm, calm days. During spring the lake usually stays cool, often between the low 40s and mid 60s°F (4–18°C) as it thermally stratifies, while fall sees a steady cooling into the 50s–60s°F (10–20°C) range. In winter the surface temperature approaches freezing, around 32–40°F (0–4°C), and the lake often develops ice cover, ending open-water conditions.
Swimming in Lake Keesus is generally allowed and commonly practiced from shorelines, private lots, and municipal access sites when conditions are favorable. Availability depends on season and local rules: warm summer temperatures make swimming comfortable, but water quality advisories for algae or bacteria can temporarily restrict swimming. In addition, safety considerations—such as cold spring or autumn water, boat traffic, and winter ice—affect when and where it is appropriate to enter the water. Visitors should observe posted signs and local guidance because access and advisories vary by site and time of year.