Brownlee Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Brownlee Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Brownlee Reservoir today is 20.8°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 68°F (20°C) to 74°F (23°C). The water is warm and pleasant for swimming, and in this range, one can stay in the water for extended periods without the risk of hypothermia. This is the ideal temperature for relaxation, swimming, and water sports. Families with children, as well as outdoor enthusiasts, will enjoy swimming and time spent in the water. For most people, this is the optimal temperature for a comfortable beach experience. 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 | 21.1°C | 20.5°C | |
| JUN 4 | 21.2°C | 20.5°C | |
| JUN 5 | 21.4°C | 20.5°C | |
| JUN 6 | 21.4°C | 20.5°C | |
| JUN 7 | 22.0°C | 20.5°C | |
| JUN 8 | 21.3°C | 20.5°C | |
| JUN 11 | 20.5°C | 20.8°C | |
| JUN 12 | 20.5°C | 20.8°C | |
| JUN 13 | 20.5°C | 20.8°C | |
| JUN 14 | 20.5°C | 20.7°C | |
| JUN 15 | 20.5°C | 20.7°C | |
| JUN 16 | 20.5°C | 20.7°C | |
| JUN 17 | 20.5°C | 20.7°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 | 6°C |
| February | 2°C | 5°C | 8°C |
| March | 3°C | 7°C | 11°C |
| April | 6°C | 11°C | 15°C |
| May | 14°C | 18°C | 23°C |
| June | 17°C | 21°C | 24°C |
| July | 21°C | 26°C | 31°C |
| August | 24°C | 27°C | 30°C |
| September | 21°C | 24°C | 26°C |
| October | 14°C | 18°C | 22°C |
| November | 8°C | 12°C | 14°C |
| December | 4°C | 7°C | 9°C |
Brownlee Reservoir: Water Temperature by Location
Brownlee Reservoir: Weather Forecast
June 9
June 10
June 11
June 12
Location & Local Information
Brownlee Reservoir on the Idaho-Oregon border typically stays cool for much of the year. Surface temperatures in spring are commonly in the 40–60°F range (4–16°C) as snowmelt and inflows keep the water brisk. In summer, shallow areas and protected bays can warm to roughly 60–75°F (15–24°C) on warm afternoons, though open-water and deeper zones remain significantly cooler. By fall the surface usually falls back into the 45–60°F (7–16°C) range, and winter temperatures often hover near freezing at 32–40°F (0–4°C) where ice or slush can form in sheltered spots. Thermal stratification means deeper water can be much colder year-round, increasing the risk of cold shock if one dives or drops below the warm surface layer.
Swimming is commonly practiced at Brownlee’s shorelines and coves because the reservoir is a multiuse recreational resource, but it is not the same as a lifeguarded beach. Many areas are open to swimmers, yet there are safety considerations: cold water, boat traffic, underwater hazards, and restricted zones near the dam and spillway where swimming is prohibited for safety and operational reasons. Seasonal cold and the possibility of sudden temperature changes make hypothermia a real concern; swimmers should choose sheltered, shallow areas, wear flotation or wetsuits in cooler months, and follow posted restrictions and local guidance.