Grindstone Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Grindstone Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Grindstone Lake today is 17.8°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 60°F (15°C) to 65°F (18°C). The water is comfortable for most people, making it an ideal range for water sports enthusiasts. The temperature does not cause significant discomfort, and swimming will be pleasant for the majority. However, it's important to remember that prolonged exposure to the water can still lead to cooling, so it's essential to monitor the time spent in the water, especially for children or elderly people. 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 | 19.8°C | 17.7°C | |
| SEP 15 | 18.5°C | 17.7°C | |
| SEP 16 | 18.5°C | 17.7°C | |
| SEP 17 | 18.4°C | 17.7°C | |
| SEP 18 | 17.8°C | 17.7°C | |
| SEP 19 | 18.0°C | 17.7°C | |
| SEP 20 | 17.9°C | 17.7°C | |
| SEP 22 | 17.7°C | 17.8°C | |
| SEP 23 | 17.7°C | 17.8°C | |
| SEP 24 | 17.7°C | 17.8°C | |
| SEP 25 | 17.7°C | 17.8°C | |
| SEP 26 | 17.7°C | 17.8°C | |
| SEP 27 | 17.7°C | 17.8°C | |
| SEP 28 | 17.7°C | 17.8°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 | 3°C | 7°C |
| February | 0°C | 3°C | 6°C |
| March | 0°C | 4°C | 8°C |
| April | 1°C | 6°C | 11°C |
| May | 8°C | 14°C | 19°C |
| June | 15°C | 18°C | 22°C |
| July | 19°C | 23°C | 27°C |
| August | 18°C | 24°C | 30°C |
| September | 14°C | 18°C | 22°C |
| October | 9°C | 14°C | 18°C |
| November | 3°C | 8°C | 13°C |
| December | 0°C | 3°C | 7°C |
Grindstone Lake: Water Temperature by Location
Grindstone Lake: Weather Forecast
September 22
September 23
September 24
September 25
Location & Local Information
Grindstone Lake in northern Wisconsin follows the seasonal pattern typical of glacial lakes in the region. After ice-out in spring, surface temperatures often rise from the low 40s to mid-60s °F (about 5–18 °C) through May and June as sun and air temperatures warm the water. Peak summer surface temperatures commonly reach the low to upper 70s °F (around 21–26 °C), with shallow bays occasionally climbing into the low 80s °F (27–28 °C) on hot, calm days. By early fall the lake cools back into the 50s–60s °F (10–16 °C) and then drops toward the mid-30s–40s °F (2–6 °C) under and after ice formation in winter when the surface is near freezing (32 °F / 0 °C) and the deeper water is typically closer to 39 °F (4 °C).
Swimming at Grindstone Lake is generally allowed and is a common recreational use in summer because surface temperatures become comfortable for bathing and there are shoreline access points. Seasonal swimming depends on conditions: water that is too cold in spring or late fall poses hypothermia risk, and winter ice cover prevents open-water swimming. As with any inland lake, local water-quality advisories, beach postings, and safety measures (life jackets, supervision, awareness of algae blooms or weather changes) determine when and where it is advisable to swim.