Lake Jefferson — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Jefferson, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Jefferson today is 12.9°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 54°F (12°C) to 60°F (15°C). The water is significantly warmer, and swimming becomes possible for most people. However, caution may still be required for prolonged stays in the water, as extended exposure can cause discomfort. This is a suitable temperature range for short swims and for those accustomed to cooler water. For more comfortable swimming, it is recommended to use proper gear. 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 |
|---|---|---|---|
| OCT 5 | 15.0°C | 13.0°C | |
| OCT 6 | 14.5°C | 13.0°C | |
| OCT 7 | 13.5°C | 13.0°C | |
| OCT 8 | 14.1°C | 13.0°C | |
| OCT 9 | 13.9°C | 13.0°C | |
| OCT 10 | 13.6°C | 13.0°C | |
| OCT 11 | 12.9°C | 13.0°C | |
| OCT 12 | 13.3°C | 13.0°C | |
| OCT 13 | 13.0°C | 12.9°C | |
| OCT 14 | 13.0°C | 12.9°C | |
| OCT 15 | 13.0°C | 12.9°C | |
| OCT 16 | 13.0°C | 12.9°C | |
| OCT 17 | 13.0°C | 12.9°C | |
| OCT 18 | 13.0°C | 12.9°C | |
| OCT 19 | 13.0°C | 12.9°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 | 4°C | 8°C |
| February | 0°C | 4°C | 8°C |
| March | 0°C | 4°C | 9°C |
| April | 3°C | 9°C | 16°C |
| May | 10°C | 16°C | 21°C |
| June | 16°C | 22°C | 27°C |
| July | 20°C | 24°C | 28°C |
| August | 21°C | 25°C | 28°C |
| September | 18°C | 21°C | 23°C |
| October | 6°C | 13°C | 20°C |
| November | 3°C | 7°C | 12°C |
| December | 1°C | 4°C | 8°C |
Lake Jefferson: Water Temperature by Location
Lake Jefferson: Weather Forecast
October 13
October 14
October 15
October 16
October 17
Location & Local Information
Lake Jefferson follows the typical Minnesota lake seasonal pattern. During winter months the surface is commonly frozen and water under the ice sits just above freezing, around 32–39°F (0–4°C). In spring, melting and runoff keep temperatures cool, often ranging from about 35–55°F (2–13°C) as the lake stratifies. Summer brings the warmest conditions; surface temperatures often reach roughly 65–78°F (18–26°C), with occasional late-summer warm spells pushing toward the low 80s°F (around 27–28°C) in shallow areas. In autumn the lake cools again, dropping back through the 50s–40s°F (10–4°C) as surface cooling and turnover occur.
Swimming is generally allowed on Lake Jefferson during the ice-free season at public access points and any designated beaches, but conditions and rules are set locally and can vary. Water temperature and weather strongly influence comfort and safety: many swimmers find water above the mid-60s°F (about 18°C) comfortable for brief swims, while prolonged exposure in colder water increases risk of hypothermia. Seasonal issues such as blue‑green algal blooms, bacterial advisories or boating traffic can also limit safe swimming, so observers should heed current health advisories, posted signs and county or township guidance, and avoid entering the water when ice is present.