Lake Geneva — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Geneva, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Geneva today is 20°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 13 | 20.9°C | 20.5°C | |
| SEP 14 | 21.5°C | 20.5°C | |
| SEP 15 | 20.9°C | 20.5°C | |
| SEP 16 | 20.0°C | 20.5°C | |
| SEP 17 | 20.5°C | 20.5°C | |
| SEP 18 | 20.5°C | 20.5°C | |
| SEP 19 | 20.4°C | 20.5°C | |
| SEP 20 | 19.6°C | 20.5°C | |
| SEP 21 | 20.5°C | 20.0°C | |
| SEP 22 | 20.5°C | 20.1°C | |
| SEP 23 | 20.5°C | 20.1°C | |
| SEP 24 | 20.5°C | 20.1°C | |
| SEP 25 | 20.5°C | 20.1°C | |
| SEP 26 | 20.5°C | 20.2°C | |
| SEP 27 | 20.5°C | 20.2°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 | 3°C | 6°C |
| February | 0°C | 3°C | 6°C |
| March | 1°C | 5°C | 8°C |
| April | 5°C | 9°C | 13°C |
| May | 9°C | 14°C | 19°C |
| June | 15°C | 19°C | 23°C |
| July | 20°C | 25°C | 30°C |
| August | 22°C | 25°C | 27°C |
| September | 17°C | 21°C | 24°C |
| October | 13°C | 17°C | 20°C |
| November | 3°C | 7°C | 11°C |
| December | 0°C | 4°C | 8°C |
Lake Geneva: Water Temperature by Location
Lake Geneva: Weather Forecast
September 21
September 22
September 23
September 24
September 25
September 26
Location & Local Information
Lake Geneva in Wisconsin experiences a wide range of water temperatures through the year. In winter the lake commonly has surface readings near freezing, about 32–40°F (0–4°C) when open water exists and often ice cover develops. Spring temperatures typically climb from roughly 40–60°F (4–15°C) as the lake stratifies and thaws. The warmest period is summer, with surface temperatures most often in the 70–80°F range (21–27°C) and occasionally reaching the mid‑80s (around 29°C) on hot, calm days. By autumn the water cools again to roughly 50–65°F (10–18°C) as heat loss increases and turnover begins.
Swimming in Lake Geneva is permitted and commonly practiced during the warmer months at public beaches and park swim areas, where lifeguards and designated swimming zones are provided for safety. Restrictions are typically seasonal: water-based recreation is discouraged or prohibited when the lake is ice‑covered or during official water‑quality advisories. Local health departments monitor bacterial counts and harmful algal blooms and will issue short‑term advisories if conditions pose risks. Even when temperatures are comfortable, swimmers should heed posted signs and local guidance for safety and water‑quality updates.