Island Lake Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Island Lake Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Island Lake Reservoir today is 17.5°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 |
|---|---|---|---|
| JUN 23 | 16.7°C | 18.0°C | |
| JUN 24 | 16.6°C | 18.0°C | |
| JUN 25 | 16.6°C | 18.0°C | |
| JUN 26 | 16.9°C | 18.0°C | |
| JUN 27 | 17.1°C | 18.0°C | |
| JUN 28 | 17.3°C | 18.0°C | |
| JUN 29 | 17.5°C | 18.0°C | |
| JUN 30 | 17.5°C | 18.0°C | |
| JUL 1 | 23.0°C | 17.8°C | |
| JUL 2 | 23.0°C | 18.1°C | |
| JUL 3 | 23.0°C | 18.3°C | |
| JUL 4 | 23.0°C | 18.6°C | |
| JUL 5 | 23.0°C | 18.9°C | |
| JUL 6 | 23.0°C | 19.2°C | |
| JUL 7 | 23.0°C | 19.4°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 | 5°C | 9°C |
| May | 3°C | 10°C | 18°C |
| June | 15°C | 18°C | 21°C |
| July | 19°C | 23°C | 27°C |
| August | 18°C | 24°C | 30°C |
| September | 14°C | 16°C | 19°C |
| October | 9°C | 13°C | 17°C |
| November | 1°C | 6°C | 11°C |
| December | 0°C | 2°C | 4°C |
Island Lake Reservoir: Water Temperature by Location
Island Lake Reservoir: Weather Forecast
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Location & Local Information
Island Lake Reservoir in Minnesota experiences strong seasonal shifts in water temperature typical of inland northern reservoirs. During winter the surface is often at or just below freezing, around 32°F (0°C) where ice forms and open water is scarce. In spring the reservoir thaws and temperatures commonly range from about 40–60°F (4–16°C) as the water mixes and warms. Peak summer surface temperatures are usually reached in July and August, commonly sitting between roughly 68–78°F (20–26°C) in warm years, making conditions most comfortable for recreational swimming. In autumn the water cools again, generally falling into the 50–60°F (10–16°C) range before freezing resumes.
Swimming at Island Lake Reservoir is generally feasible during the ice-free months when local conditions are safe, but it depends on water quality, visible hazards, and any posted regulations. Mid-summer offers the most comfortable temperatures for casual swimmers because the surface water is warmest; spring and fall can still feel uncomfortably cold and increase risk of hypothermia for prolonged exposure. Winter swimming is not advised because of ice hazards and dangerously low water temperatures. Visitors should check local signage, community guidance, and recent water-quality reports before swimming to ensure safety.