Okauchee Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Okauchee Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Okauchee Lake today is 19.6°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming. 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 |
|---|---|---|---|
| SEP 14 | 19.7°C | 21.0°C | |
| SEP 15 | 19.9°C | 21.0°C | |
| SEP 16 | 19.6°C | 21.0°C | |
| SEP 17 | 19.8°C | 21.0°C | |
| SEP 18 | 19.4°C | 21.0°C | |
| SEP 19 | 19.4°C | 21.0°C | |
| SEP 20 | 19.1°C | 21.0°C | |
| SEP 22 | 21.0°C | 19.7°C | |
| SEP 23 | 21.0°C | 19.7°C | |
| SEP 24 | 21.0°C | 19.8°C | |
| SEP 25 | 21.0°C | 19.9°C | |
| SEP 26 | 21.0°C | 20.0°C | |
| SEP 27 | 21.0°C | 20.0°C | |
| SEP 28 | 21.0°C | 20.1°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 | 6°C | 13°C | 19°C |
| June | 16°C | 19°C | 23°C |
| July | 20°C | 25°C | 30°C |
| August | 22°C | 25°C | 27°C |
| September | 18°C | 21°C | 24°C |
| October | 13°C | 17°C | 20°C |
| November | 3°C | 9°C | 15°C |
| December | 0°C | 3°C | 6°C |
Okauchee Lake: Water Temperature by Location
Okauchee Lake: Weather Forecast
September 21
September 22
September 23
September 24
September 25
September 26
Location & Local Information
Okauchee Lake in Waukesha County experiences typical Midwestern seasonal temperature swings. Surface water in spring commonly ranges from about 40–60°F (4–16°C) as the lake stratifies and warms. In summer, when conditions are greatest for swimming, surface temperatures most often reach roughly 70–80°F (21–27°C), though shallow bays may be warmer and deeper spots a few degrees cooler. During fall the lake cools back to roughly 50–65°F (10–18°C) before winter sets in, when surface water approaches freezing — roughly 32–39°F (0–4°C) — and the lake frequently develops ice cover.
Swimming at Okauchee Lake is generally permitted and is a common recreational activity from late spring through early fall because of public access points and private shoreline use. Whether it’s advisable to swim depends on conditions: warm summer temperatures make swimming comfortable, but local health advisories, beach closures, or harmful algal blooms can temporarily prohibit swimming for safety. In winter, ice and very cold water make swimming unsafe except for organized, properly equipped winter-swim events. Visitors should heed posted signs and any advisories from local authorities before entering the water.