Half Moon Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Half Moon Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Half Moon Lake today is 19.1°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 | 20.9°C | 18.8°C | |
| SEP 15 | 19.7°C | 18.8°C | |
| SEP 16 | 19.8°C | 18.8°C | |
| SEP 17 | 20.1°C | 18.8°C | |
| SEP 18 | 19.1°C | 18.8°C | |
| SEP 19 | 19.7°C | 18.8°C | |
| SEP 20 | 19.5°C | 18.8°C | |
| SEP 21 | 19.1°C | 18.8°C | |
| SEP 22 | 18.8°C | 19.1°C | |
| SEP 23 | 18.8°C | 19.1°C | |
| SEP 24 | 18.8°C | 19.1°C | |
| SEP 25 | 18.8°C | 19.0°C | |
| SEP 26 | 18.8°C | 19.0°C | |
| SEP 27 | 18.8°C | 19.0°C | |
| SEP 28 | 18.8°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 | 1°C | 3°C |
| February | 0°C | 1°C | 3°C |
| March | 0°C | 2°C | 5°C |
| April | 1°C | 8°C | 16°C |
| May | 8°C | 15°C | 22°C |
| June | 15°C | 19°C | 24°C |
| July | 21°C | 24°C | 28°C |
| August | 20°C | 25°C | 30°C |
| September | 14°C | 19°C | 24°C |
| October | 9°C | 14°C | 19°C |
| November | 3°C | 8°C | 12°C |
| December | 0°C | 2°C | 4°C |
Half Moon Lake: Water Temperature by Location
Half Moon Lake: Weather Forecast
September 21
September 22
September 23
September 24
September 25
Location & Local Information
Half Moon Lake in Wisconsin experiences the seasonal temperature swings typical of small northern temperate lakes. In spring the surface water commonly ranges from about 45–60°F (7–16°C) as warming follows ice-out. Peak summer surface temperatures often reach roughly 70–80°F (21–27°C) on warm, calm days, though deeper water remains cooler. By early fall the lake cools to roughly 50–65°F (10–18°C) and then drops quickly as autumn progresses toward ice formation; winter conditions produce ice cover and near-freezing water beneath, around 32–34°F (0–1°C).
Swimming at Half Moon Lake is generally possible during the ice-free months. Public access and recreational use usually permit swimming, and summer surface temperatures are warm enough for comfortable recreational bathing. However, safety and comfort depend on conditions: late spring and early fall can be uncomfortably cold and pose cold-shock risks, and there may be no lifeguards or posted water-quality testing at every access point. Local rules, water-quality advisories, and seasonal restrictions—plus common-sense precautions like checking weather, avoiding swimming alone, and observing posted signs—determine when and where it is appropriate to swim.