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 19.2°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 | 22.5°C | 20.6°C | |
| SEP 15 | 22.1°C | 20.6°C | |
| SEP 16 | 20.9°C | 20.6°C | |
| SEP 17 | 19.4°C | 20.6°C | |
| SEP 18 | 19.5°C | 20.6°C | |
| SEP 19 | 19.6°C | 20.6°C | |
| SEP 20 | 19.9°C | 20.6°C | |
| SEP 21 | 19.2°C | 20.6°C | |
| SEP 22 | 20.6°C | 19.3°C | |
| SEP 23 | 20.6°C | 19.3°C | |
| SEP 24 | 20.6°C | 19.4°C | |
| SEP 25 | 20.6°C | 19.5°C | |
| SEP 26 | 20.6°C | 19.6°C | |
| SEP 27 | 20.6°C | 19.6°C | |
| SEP 28 | 20.6°C | 19.7°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 | 5°C |
| February | 0°C | 3°C | 5°C |
| March | 0°C | 3°C | 5°C |
| April | 3°C | 8°C | 14°C |
| May | 10°C | 16°C | 23°C |
| June | 16°C | 22°C | 27°C |
| July | 21°C | 25°C | 30°C |
| August | 20°C | 24°C | 28°C |
| September | 18°C | 21°C | 23°C |
| October | 6°C | 13°C | 19°C |
| November | 3°C | 7°C | 11°C |
| December | 1°C | 3°C | 6°C |
Long Lake: Water Temperature by Location
Long Lake: Weather Forecast
September 21
September 22
September 23
September 24
September 25
September 26
Location & Local Information
Long Lake in Minnesota follows the seasonal temperature patterns typical of midwestern glacial lakes. After ice-out in spring, surface temperatures commonly rise from about 35–55°F (2–13°C) as the water warms through May and June. In summer the surface usually reaches its warmest, often ranging from roughly 70–80°F (21–27°C) on calm, sunny days, though shallower bays can heat a few degrees higher and deeper water remains cooler. By early fall the lake cools back toward 45–60°F (7–16°C) as air temperatures drop. During winter the surface freezes and water beneath the ice stays near the cold-water density range, typically around 32–39°F (0–4°C).
Swimming is commonly allowed during the ice-free months because water temperatures in summer become comfortable for recreational bathing and local parks and beaches maintain access. However, swimming is not possible or advisable when the lake is ice-covered, and local health or safety advisories can temporarily restrict swimming due to harmful algal blooms, bacterial contamination, strong winds, or hazardous conditions. Even in summer, swimmers should be aware that water below about 60°F (15°C) can induce cold-water shock and that deeper or shaded areas remain significantly colder than shallow, sun-warmed spots. Local signage and park rules are the best guides for when swimming is permitted.