Fifth Lake
Lake · 10,793 ft · Eastern Sierra corridor
Fifth Lake sits at 10,793 feet in the Eastern Sierra, a glacially-carved alpine basin accessed via the Mammoth Lakes corridor. Wind accelerates across its open water by midday, making early morning the defining window.
Fifth Lake catches afternoon wind funneling down the Eastern Sierra drainage; the 30-day average wind is 12 mph, with gusts to 41 mph common by day's end. Morning conditions are markedly calmer. Expect intense sun exposure and rapid temperature swings typical of high-elevation water.
Over the past 30 days, Fifth Lake averaged a NoGo Score of 36, with temperatures around 19 degrees Fahrenheit and the 30-day average wind of 12 mph. The week ahead follows the same pattern: stable cold mornings, escalating wind by afternoon. Plan paddling or fishing before 10 a.m. if wind sensitivity matters.
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About Fifth Lake
Fifth Lake is a high-alpine lake in the Eastern Sierra's Mammoth Lakes Basin, lying at 10,793 feet on the Cascade drainage. Access is via California Highway 203 from the town of Mammoth Lakes; the drive from the valley floor takes under 30 minutes. The lake sits in open terrain with minimal tree shelter, exposing it to sierra wind patterns. Parking fills quickly on weekends, especially as snow recedes from approach trails. Winter access requires avalanche awareness; the basin terrain holds instability in spring snowpack.
Fifth Lake behaves as a cold, wind-prone alpine water body year-round. The 30-day average temperature is 19 degrees Fahrenheit, with seasonal extremes spanning 5 to 32 degrees Fahrenheit over a rolling year. Wind averages 12 mph but routinely peaks at 41 mph in afternoon hours, driven by thermal and pressure gradients along the Sierra crest. Crowding is light (average 3 out of 10) compared to lower-elevation Mammoth Basin lakes, but weekend traffic increases sharply in late spring and early autumn when road access stabilizes. Early summer brings lingering snowpack and colder water; late September offers the most benign weather window.
Fifth Lake suits experienced paddlers, flyfishers comfortable in alpine conditions, and photographers timing light and weather. The shallow basin and open exposure demand respect for sudden wind shifts and cold-water immersion risk. Pack layers; a 19-degree average means hypothermia is a genuine hazard even in apparent summer. Afternoon wind makes this a morning-only venue for paddling or angling; attempting these activities after 10 a.m. invites difficult conditions. The lake's low popularity (0.25 relative to system baseline) reflects its remoteness and technical weather demands rather than poor fishing or scenery.
The Eastern Sierra corridor's other alpine lakes (Horseshoe, Mammoth, Twin) share similar exposure and wind character. Horseshoe Lake sits nearby with comparable elevation and slightly higher shelter from ridge wind. Crowley Lake, lower in elevation, offers calmer afternoon conditions and higher summer temperatures. For visitors committed to alpine fishing in the Mammoth basin, Fifth Lake's isolation and stable cold make it reliable for lake trout; expect to arrive before dawn and depart by early afternoon.