Lake Tomah — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Tomah, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Tomah today is 19°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 | 21.4°C | 18.3°C | |
| SEP 15 | 20.4°C | 18.3°C | |
| SEP 16 | 19.7°C | 18.3°C | |
| SEP 17 | 20.0°C | 18.3°C | |
| SEP 18 | 19.9°C | 18.3°C | |
| SEP 19 | 18.9°C | 18.3°C | |
| SEP 20 | 19.4°C | 18.3°C | |
| SEP 21 | 19.0°C | 18.3°C | |
| SEP 22 | 18.3°C | 19.0°C | |
| SEP 23 | 18.3°C | 18.9°C | |
| SEP 24 | 18.3°C | 18.9°C | |
| SEP 25 | 18.3°C | 18.9°C | |
| SEP 26 | 18.3°C | 18.8°C | |
| SEP 27 | 18.3°C | 18.8°C | |
| SEP 28 | 18.3°C | 18.8°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 | 1°C | 3°C |
| February | 0°C | 1°C | 3°C |
| March | 0°C | 2°C | 5°C |
| April | 1°C | 8°C | 15°C |
| May | 9°C | 14°C | 20°C |
| June | 15°C | 18°C | 22°C |
| July | 20°C | 24°C | 28°C |
| August | 19°C | 25°C | 30°C |
| September | 14°C | 18°C | 23°C |
| October | 9°C | 14°C | 19°C |
| November | 3°C | 9°C | 14°C |
| December | 0°C | 2°C | 4°C |
Lake Tomah: Water Temperature by Location
Lake Tomah: Weather Forecast
September 21
September 22
September 23
September 24
September 25
Location & Local Information
Lake Tomah’s surface temperature follows the familiar seasonal pattern of southern Wisconsin lakes. In winter the water hovers near freezing and is often at or just above 32°F (0°C) beneath ice, while early spring typically sees temperatures in the 40–60°F range (4–16°C) as the lake stratifies. Peak summer surface temperatures commonly reach the upper 60s to upper 70s °F, roughly 20–26°C, though shallow bays can warm several degrees higher on hot, calm days. In autumn the surface cools again to roughly 50–65°F (10–18°C) before overturn in late fall. Deeper water stays considerably colder year-round, so thermal layering and rapid changes near the surface are normal.
Swimming at Lake Tomah is generally allowed at public access points and designated recreational areas because the lake is used for community recreation and managed by local authorities. Whether swimming is advisable depends on current conditions: posted water-quality advisories, visible harmful algal blooms, boat traffic, and ice cover can make swimming unsafe at times. Cold water and sudden drops in temperature by depth also pose hypothermia risk even in warm months. Visitors should follow local signage, heed official advisories, and choose supervised beaches when available for the safest swimming experience.