Pool 5 Mississippi Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Pool 5 Mississippi Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Pool 5 Mississippi Lake today is 18.9°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 | 20.6°C | 19.2°C | |
| SEP 15 | 20.5°C | 19.2°C | |
| SEP 16 | 20.5°C | 19.2°C | |
| SEP 17 | 19.5°C | 19.2°C | |
| SEP 18 | 19.0°C | 19.2°C | |
| SEP 19 | 19.5°C | 19.2°C | |
| SEP 20 | 19.8°C | 19.2°C | |
| SEP 21 | 18.9°C | 19.2°C | |
| SEP 22 | 19.2°C | 18.9°C | |
| SEP 23 | 19.2°C | 18.9°C | |
| SEP 24 | 19.2°C | 18.9°C | |
| SEP 25 | 19.2°C | 19.0°C | |
| SEP 26 | 19.2°C | 19.0°C | |
| SEP 27 | 19.2°C | 19.0°C | |
| SEP 28 | 19.2°C | 19.0°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 | 0°C | 1°C | 3°C |
| March | 0°C | 3°C | 7°C |
| April | 1°C | 8°C | 15°C |
| May | 9°C | 16°C | 23°C |
| June | 16°C | 20°C | 24°C |
| July | 22°C | 25°C | 29°C |
| August | 21°C | 26°C | 30°C |
| September | 14°C | 19°C | 25°C |
| October | 9°C | 14°C | 19°C |
| November | 3°C | 8°C | 12°C |
| December | 0°C | 2°C | 4°C |
Pool 5 Mississippi Lake: Water Temperature by Location
Pool 5 Mississippi Lake: Weather Forecast
September 22
September 23
September 24
September 25
Location & Local Information
Pool 5 of the Mississippi River, the impounded reach downstream of Lock and Dam No. 5 that touches Wisconsin shoreline, experiences pronounced seasonal swings in water temperature. In winter the surface often approaches freezing, roughly 32–40°F (0–4°C) where open water remains, while spring thaw and runoff typically raise temperatures into the 40s and low 60s°F (4–16°C). During summer, shallower backwater bays and slow-moving side channels commonly warm to the mid‑60s up through the upper 70s°F (18–26°C) and on hot, calm days localized spots can reach around 80°F (27°C). Deeper navigation channels and areas with steady flow stay cooler. As autumn arrives the water drops through the 50s°F (10–15°C) and toward freeze-up again.
Swimming in Pool 5 is possible in some public access and park areas but is not uniformly recommended across the entire pool. Designated swimming spots and calmer backwaters with gradual shores offer the safest opportunities, whereas the main channel near locks, dams and boat traffic has strong currents, submerged hazards and variable water quality—issues that make swimming unsafe there. Local signage, seasonal algae advisories and municipal rules determine where swimming is allowed; visitors should choose authorized areas and be mindful that conditions change with river levels and weather.