Mount Cotter
Peak · 12,727 ft · Eastern Sierra corridor
Mount Cotter is a 12,727 ft peak in California's Eastern Sierra, sitting east of the Sierra crest near Inyo County. A moderate alpine scramble with exposure to afternoon wind and seasonal snow.
Wind accelerates up the eastern slope by midday, funneling off the high desert floor below. Morning calm windows are brief and narrow. Snow persists into late spring, and exposure increases substantially above 12,000 ft. Afternoon gusts can exceed 30 mph.
Over the last 30 days, Mount Cotter has averaged a NoGo Score of 37.0, with wind averaging 13.0 mph but peaking at 37.0 mph. Temperatures remain cool at 23.0 F average, and crowds stay low (2.0 on the scale). The week ahead will test whether early-season windows hold before thermal heating drives stronger afternoon flows.
30 days back / 7 days forward
Today's score by factor
About Mount Cotter
Mount Cotter sits on the Eastern Sierra crest, 12,727 ft, accessed primarily from the Inyo National Forest via US 395 south of Mammoth Lakes. The peak lies in the high alpine zone east of the main Sierra ridge, with direct exposure to Owens Valley winds. Most approaches start from trailheads along Highway 395 or forest service roads in the Bishop or Mammoth areas. Drive times from Mammoth Lakes run 45 minutes to 90 minutes depending on road conditions and trailhead choice. The peak is technical scrambling rather than hiking; snow and rock both demand sure footing.
The 30-day average wind of 13.0 mph masks violent afternoon acceleration; maximum gusts have reached 37.0 mph in the rolling 30-day window. Temperatures average 23.0 F, with a year-round minimum of 6.0 F and maximum of 35.0 F. Spring and early summer bring snowpack instability and avalanche risk on the approach slopes; the Eastern Sierra Avalanche Center maintains forecasts for the corridor. Crowds remain minimal (2.0 on the NoGo scale average), a function of the peak's technical difficulty and remote access. Late spring through early fall offers the longest stable windows, though thermal wind develops by late morning even in those months.
Mount Cotter suits experienced alpine scramblers comfortable with exposure, rock, and self-rescue. Parties without winter mountaineering skills should avoid the peak in snow; late September through mid-October offers the most reliable off-snow window. Wind is the dominant annoyance; head out by dawn and plan descent before 1 PM to dodge peak gusts. Bring extra layers; the 12,700 ft elevation sits above most weather systems, and wind chill erases the apparent temperature advantage of spring or fall ascents. Parking at forest service trailheads fills by mid-morning on weekends.
Nearby alternatives in the Eastern Sierra corridor include Mount Tom, Mount Humphreys, and Basin Mountain; all sit in the same wind shadow and elevation band. Mount Cotter's lower profile and less-documented routes make it quieter than Humphreys but no less demanding. Winter access is possible for equipped parties, but avalanche terrain dominates the approach; consult ESAC forecasts before attempting December through April ascents. The peak rewards early starters and wind-aware climbers; afternoon visitors encounter conditions deteriorated from morning.