Long Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Long Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Long Lake today is 19.9°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 |
|---|---|---|---|
| AUG 24 | 22.6°C | 24.5°C | |
| AUG 25 | 22.3°C | 24.5°C | |
| AUG 26 | 20.8°C | 24.5°C | |
| AUG 27 | 19.4°C | 24.5°C | |
| AUG 28 | 19.4°C | 24.5°C | |
| AUG 29 | 19.6°C | 24.5°C | |
| AUG 30 | 19.6°C | 24.5°C | |
| AUG 31 | 19.6°C | 24.5°C | |
| SEP 1 | 16.1°C | 19.7°C | |
| SEP 2 | 16.1°C | 19.5°C | |
| SEP 3 | 16.1°C | 19.3°C | |
| SEP 4 | 16.1°C | 19.1°C | |
| SEP 5 | 16.1°C | 19.0°C | |
| SEP 6 | 16.1°C | 18.8°C | |
| SEP 7 | 16.1°C | 18.6°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 | 4°C |
| April | 1°C | 7°C | 12°C |
| May | 7°C | 14°C | 20°C |
| June | 15°C | 19°C | 23°C |
| July | 20°C | 24°C | 27°C |
| August | 19°C | 25°C | 30°C |
| September | 14°C | 16°C | 19°C |
| October | 9°C | 14°C | 18°C |
| November | 1°C | 7°C | 12°C |
| December | 0°C | 0°C | 2°C |
Long Lake: Water Temperature by Location
Long Lake: Weather Forecast
September 1
September 2
September 3
September 4
September 5
September 6
Location & Local Information
Long Lake in Wisconsin experiences a wide range of surface temperatures through the year, driven by seasonal air temperatures and depth variation. In spring the water typically runs cool, roughly 45–65°F (7–18°C) as the lake stratifies and warms. Peak summer surface temperatures are usually in the 70–80°F range (21–27°C), and on warm, shallow bays can climb into the mid-80s (~29°C) on hot afternoons. By fall the surface cools again to roughly 45–60°F (7–16°C) as turnover approaches, and in winter the lake surface approaches freezing near 32°F (0°C) where ice forms, making open-water swimming unsafe. Temperatures vary by depth, wind exposure and time of day, so readings from a protected bay will differ from those in deeper central basins.
Swimming is generally permitted at Long Lake where public access or private beaches exist, and many people swim in summer when surface temperatures are most comfortable. Local rules, posted advisories and water-quality testing determine whether bathing is allowed at specific sites; blue‑green algae (cyanobacteria) blooms or bacterial contamination can lead to temporary closures. Cold spring and fall water temperatures and winter ice make prolonged swimming hazardous because of cold‑shock and hypothermia risk, so swimmers should check current conditions and follow posted guidance before entering the water.