The Hells Canyon Dam controls water flow on the Snake River so there are consistent and excellent levels year-round. The highest water is typically in June and September. Air temperatures in the spring and fall range from 65-85 degrees and most nights cool to around 45-50 degrees Fahrenheit. It's warmer in late June through late August with daytime temperatures between 85-95 degrees, dropping to 65-70 degrees at night.
It rarely rains in Hells Canyon, but sometimes we'll witness a dramatic thundershower which instantly freshens the air. Water temperatures are usually around 60 degrees in June and September, and 70 degrees in July and August.
On the river, it's important to be prepared for all types of weather. Although the weather is warm and sunny for the most part, Mother Nature will occasionally surprise us with a renewing rainstorm or cooler temperatures. Temperatures can vary, but the following chart shows average temperature and precipitation for the months of May through September.
|Mean Max. Temp||-||-||69°||82°||92°||94°||82°||-|
|Mean Min. Temp.||-||-||40°||51°||58°||56°||47°||-|
NOTE: Use this weather forecast only as a general guide. As your trip will span miles of river, this forecast from the nearest major weather station may not be indicative of the entire region where your trip will take place. Weather in the canyon may vary greatly from the surrounding cities.
TIP: Since weather conditions can be unpredictable and river water in the Hell's Canyon averages 65°, we recommend having a two-piece rain suit available during the day. You may wish to fold it tightly and keep it in your personal day-use dry bag. (See recommended packing list).