Flathead LakeWater Level & Temperature
Flathead Lake water level & water temperature
Flathead Lake water level is updated continuously from USGS gauge 12371550 (Somers). Typical level elevation is 2893 ft. Live reading, 7-day trend, and multi-year history appear below as the data loads.
Flathead Lake water temperature by month
Flathead Lake surface water temperature averages from about 36°F in February to 69°F in August over the year, based on a 40-year USGS model (1980–2020). Cold-water caution applies in roughly half the year, when the typical temperature is below 60°F.
Jan
39°
Feb
36°
Mar
37°
Apr
45°
May
53°
Jun
60°
Jul
68°
Aug
69°
Sep
64°
Oct
58°
Nov
49°
Dec
42°
Typical surface temperatures (°F), modeled historical averages (USGS 185k-lake dataset, 1980–2020). Colors flag cold-water risk: blue/amber/red = cool, caution, danger. Live and recent readings appear above where a sensor is available.