Lake Koshkonong — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Koshkonong, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Koshkonong today is 21.7°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 3 | 20.5°C | 20.5°C | |
| JUN 4 | 20.5°C | 20.5°C | |
| JUN 5 | 20.7°C | 20.5°C | |
| JUN 6 | 21.1°C | 20.5°C | |
| JUN 7 | 21.5°C | 20.5°C | |
| JUN 8 | 21.8°C | 20.5°C | |
| JUN 10 | 21.7°C | 20.5°C | |
| JUN 11 | 20.5°C | 21.6°C | |
| JUN 12 | 20.5°C | 21.6°C | |
| JUN 13 | 20.5°C | 21.5°C | |
| JUN 14 | 20.5°C | 21.5°C | |
| JUN 15 | 20.5°C | 21.4°C | |
| JUN 16 | 20.5°C | 21.3°C | |
| JUN 17 | 20.5°C | 21.3°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 | 10°C | 14°C |
| May | 9°C | 16°C | 21°C |
| June | 17°C | 21°C | 24°C |
| July | 20°C | 26°C | 31°C |
| August | 21°C | 24°C | 26°C |
| September | 18°C | 21°C | 24°C |
| October | 6°C | 13°C | 20°C |
| November | 2°C | 9°C | 15°C |
| December | 0°C | 3°C | 5°C |
Lake Koshkonong: Water Temperature by Location
Lake Koshkonong: Weather Forecast
June 9
June 10
June 11
June 12
Location & Local Information
Lake Koshkonong is a relatively shallow, broad lake on the Rock River, so its surface temperatures respond quickly to seasonal conditions. In winter the lake commonly sits near freezing, around 30–35°F (−1 to 2°C) and can ice over at times. Spring brings a steady warm-up, with surface readings typically rising through the 40s and 50s°F (4–15°C) as melt and runoff occur. By summer, surface temperatures often reach the 70s to low 80s°F (about 21–28°C) on warm days and can occasionally climb higher during heat waves. In fall the lake cools back into the 50s and 40s°F (10–7°C) as air temperatures drop and stratification breaks down.
Swimming is allowed at many public access points on Lake Koshkonong, but conditions are variable and merit caution. The lake’s shallow depth and expansive littoral zones make water murky and warm quickly, which can encourage aquatic plants and algal blooms that sometimes lead to advisories; boat traffic and submerged vegetation also create hazards in some areas. Some access sites are ungarded, so swimmers should consider water clarity, current local water-quality notices, and boating activity before entering. During winter months ice thickness rather than temperature dictates whether any recreation on the lake is safe.