Hells Canyon Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Hells Canyon Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Hells Canyon Reservoir today is 18.4°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 | 18.3°C | 17.5°C | |
| JUN 4 | 18.5°C | 17.5°C | |
| JUN 5 | 18.4°C | 17.5°C | |
| JUN 6 | 18.5°C | 17.5°C | |
| JUN 7 | 19.7°C | 17.5°C | |
| JUN 8 | 18.7°C | 17.5°C | |
| JUN 10 | 18.4°C | 17.5°C | |
| JUN 11 | 17.5°C | 18.4°C | |
| JUN 12 | 17.5°C | 18.3°C | |
| JUN 13 | 17.5°C | 18.3°C | |
| JUN 14 | 17.5°C | 18.2°C | |
| JUN 15 | 17.5°C | 18.2°C | |
| JUN 16 | 17.5°C | 18.1°C | |
| JUN 17 | 17.5°C | 18.1°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 | 5°C | 10°C |
| February | 2°C | 6°C | 10°C |
| March | 4°C | 8°C | 12°C |
| April | 6°C | 10°C | 14°C |
| May | 8°C | 15°C | 21°C |
| June | 13°C | 18°C | 22°C |
| July | 17°C | 23°C | 29°C |
| August | 21°C | 26°C | 30°C |
| September | 19°C | 23°C | 26°C |
| October | 11°C | 15°C | 19°C |
| November | 8°C | 10°C | 13°C |
| December | 3°C | 6°C | 10°C |
Hells Canyon Reservoir: Water Temperature by Location
Hells Canyon Reservoir: Weather Forecast
June 9
June 10
June 11
June 12
June 13
Location & Local Information
Hells Canyon Reservoir, impounded on the Snake River along the Idaho–Oregon border, tends to have cool water year-round because of its depth and river inflow. Seasonal surface temperatures commonly range from about 40–55°F (4–13°C) in spring as snowmelt and runoff cool the basin, rise to roughly 60–70°F (15–21°C) in summer in sheltered shallows (with shallow coves occasionally reaching around 75°F / 24°C on very warm days), fall cooling back toward 50–60°F (10–16°C), and winter surface readings near 34–45°F (1–7°C) when cold air and reduced solar input dominate. Deeper water stays colder than surface readings, often several degrees lower, because of stratification and continual river exchange.
Swimming is generally permitted in the reservoir, but it is not a supervised or developed public beach in most spots, and several safety considerations affect whether people choose to swim. Cold-water shock and rapid loss of body heat are real risks at the typical temperatures, especially outside mid-summer, and strong currents, boat traffic, limited access points, steep drop-offs, and proximity to dam structures can make certain areas hazardous or restricted. Visitors should check local signs and operator guidance, use flotation aides or wetsuits in cooler conditions, avoid restricted zones near dams, and recognize there are usually no lifeguards on duty.