The rest of the year they are open intermittently. Headquarters is open weekdays year-round. Schedules of special events, including evening programs, hikes, and water activities, are posted. Activities Afloat Coulee Dam National Recreation Area stretches 130 miles along the length of Lake Roosevelt and embraces the lower reaches of many rivers and streams, including the Spokane and Kettle Rivers. Most of the water comes from glacial ice, lakes, and snow high in the Canadian Rockies.
Currents run slowly in the lake, swifter in the rivers and streams.
Lake water temperatures rise slowly from June, when they range from 60 F, to August, when temperatures reach 70 s F. Temperatures vary only slightly from north to south, but the Spokane River arm tends to be 5 -8 F warmer than the rest of the lake. Lake level also varies according to season. The lake is highest from late June through most of the winter. In late winter and early spring the water level is lowered as much as 100 feet to accommodate spring runoff.