Donner Lake water temperature varies from winter lows in February of around 40°F, to 72°F in summer, (or 4.5°C to 22.2°C).
Located just west of Truckee, California, Donner Lake is at its warmest in August, ranging between 65 and 72 °F (or 18.3 and 22.2°C), although these water temperatures are still considered cold and swimmers should be mindful of the risks of hypothermia.
Swimmers tend to find that water temperatures at Donner Lake’s east end are warmer than the west end where snowmelt water flows into the lake.