Lake Mendota — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Mendota, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Mendota today is 24.1°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 75°F (23°C) to 79°F (26°C). This is a very comfortable temperature for swimming, and many people can enjoy prolonged stays in the water without feeling cold. The water is pleasantly warm, making it ideal for relaxation and water sports. This temperature range is particularly popular among tourists, as it combines comfort and safety for health. 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 |
|---|---|---|---|
| JUL 14 | 19.9°C | 23.5°C | |
| JUL 15 | 22.4°C | 23.5°C | |
| JUL 16 | 22.0°C | 23.5°C | |
| JUL 17 | 22.1°C | 23.5°C | |
| JUL 18 | 23.3°C | 23.5°C | |
| JUL 19 | 22.0°C | 23.5°C | |
| JUL 20 | 24.4°C | 23.5°C | |
| JUL 21 | 24.0°C | 23.5°C | |
| JUL 22 | 23.5°C | 24.1°C | |
| JUL 23 | 23.5°C | 24.0°C | |
| JUL 24 | 23.5°C | 24.0°C | |
| JUL 25 | 23.5°C | 24.0°C | |
| JUL 26 | 23.5°C | 24.0°C | |
| JUL 27 | 23.5°C | 23.9°C | |
| JUL 28 | 23.5°C | 23.9°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 | 3°C | 6°C |
| March | 2°C | 6°C | 9°C |
| April | 4°C | 9°C | 14°C |
| May | 10°C | 14°C | 19°C |
| June | 13°C | 18°C | 23°C |
| July | 17°C | 24°C | 30°C |
| August | 17°C | 22°C | 27°C |
| September | 15°C | 19°C | 22°C |
| October | 9°C | 14°C | 18°C |
| November | 2°C | 7°C | 11°C |
| December | 0°C | 3°C | 6°C |
Lake Mendota: Water Temperature by Location
Lake Mendota: Weather Forecast
July 22
July 23
July 24
July 25
July 26
Location & Local Information
Lake Mendota, the northernmost of Madison’s four lakes, experiences wide seasonal variation in surface water temperature. In winter the lake typically hovers near freezing, around 32–39°F (0–4°C) under ice cover. Spring brings a steady warm-up, with surface temperatures commonly in the 40–60°F range (4–16°C) as stratification begins. By mid to late summer the surface often reaches roughly 68–82°F (20–28°C), and during heat waves can climb into the mid-80s°F (around 29°C). In autumn the surface cools again, generally falling through the 50s into the 40s°F (10–4°C) before refreezing; deeper water remains considerably colder year-round.
Swimming in Lake Mendota is allowed at designated beaches and parks and is a popular recreational activity in summer because surface temperatures are usually comfortable for bathing. Local agencies routinely monitor water quality and post advisories; occasional nuisance or toxic blue‑green algal blooms and bacterial spikes can lead to temporary closures for health reasons. Even when open, swimmers should be mindful of variable temperatures near shore and at depth, possible currents, and changing conditions, and they should follow posted guidance and any lifeguard instructions for safety.