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 18.6°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 |
|---|---|---|---|
| JUN 3 | 16.7°C | 18.0°C | |
| JUN 4 | 16.7°C | 18.0°C | |
| JUN 5 | 16.8°C | 18.0°C | |
| JUN 6 | 16.9°C | 18.0°C | |
| JUN 7 | 17.4°C | 18.0°C | |
| JUN 8 | 18.3°C | 18.0°C | |
| JUN 10 | 18.6°C | 18.0°C | |
| JUN 11 | 18.0°C | 18.6°C | |
| JUN 12 | 18.0°C | 18.5°C | |
| JUN 13 | 18.0°C | 18.5°C | |
| JUN 14 | 18.0°C | 18.5°C | |
| JUN 15 | 18.0°C | 18.5°C | |
| JUN 16 | 18.0°C | 18.4°C | |
| JUN 17 | 18.0°C | 18.4°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
June 9
June 10
June 11
June 12
June 13
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.