Cass Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Cass Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Cass Lake today is 19.3°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 | 17.5°C | 17.0°C | |
| JUN 4 | 17.6°C | 17.0°C | |
| JUN 5 | 17.5°C | 17.0°C | |
| JUN 6 | 18.0°C | 17.0°C | |
| JUN 7 | 18.5°C | 17.0°C | |
| JUN 8 | 18.7°C | 17.0°C | |
| JUN 10 | 19.3°C | 17.0°C | |
| JUN 11 | 17.0°C | 19.2°C | |
| JUN 12 | 17.0°C | 19.1°C | |
| JUN 13 | 17.0°C | 19.0°C | |
| JUN 14 | 17.0°C | 18.8°C | |
| JUN 15 | 17.0°C | 18.7°C | |
| JUN 16 | 17.0°C | 18.6°C | |
| JUN 17 | 17.0°C | 18.5°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 | 6°C | 12°C |
| February | 0°C | 8°C | 15°C |
| March | 0°C | 9°C | 17°C |
| April | 1°C | 11°C | 20°C |
| May | 2°C | 12°C | 21°C |
| June | 11°C | 17°C | 22°C |
| July | 17°C | 19°C | 22°C |
| August | 21°C | 25°C | 28°C |
| September | 16°C | 19°C | 22°C |
| October | 5°C | 12°C | 18°C |
| November | 2°C | 7°C | 11°C |
| December | 1°C | 6°C | 11°C |
Cass Lake: Water Temperature by Location
Cass Lake: Weather Forecast
June 9
June 10
June 11
June 12
June 13
Location & Local Information
Cass Lake in northern Minnesota experiences a wide range of water temperatures through the year because of seasonal changes and variations in depth and exposure. In spring (April–May) surface temperatures are often cold, roughly 35–55°F (2–13°C) as ice melts and runoff cools the water. By summer (June–August) the shallows typically warm to about 65–75°F (18–24°C), with the warmest conditions in July and August; deeper areas remain cooler. In fall (September–October) temperatures fall back into the 50–60°F (10–16°C) range as air temperatures drop. During winter the lake usually freezes; the ice-covered surface is at or near 32°F (0°C) while water beneath the ice generally stays around 33–39°F (1–4°C).
Swimming is commonly allowed at Cass Lake and is a normal recreational use in summer when surface temperatures are most comfortable. Public access points and shoreline areas are used for bathing and paddling, but conditions can vary: shallow bays warm faster, while open and deeper water stays brisk. Seasonal cold, sudden temperature changes, the absence of lifeguards at many spots, and occasional water-quality advisories mean swimmers should exercise caution, check local signage, and be prepared for colder-than-expected water even on warm days.