Lake Tahoe waters are warming in response to changing climate conditions in the Sierra Nevada.

Climate change is among the greatest threats to lakes. Lakes are sensitive to climate and respond rapidly to change, and thus serve as good sentinels for climate change. Mountain lakes may be particularly sensitive in part because high-elevation ecosystems are warming very quickly. Aquatic habitats most vulnerable to climate effects, especially rising temperatures, are alpine lakes like Lake Tahoe that sit at high altitudes. For more information, download the Lake Water Temperature chapter.

Lake Tahoe is famous for its clarity and stunning cobalt blue hue. It spans 22 miles and has a maximum depth of 1,644 feet, making it the third-deepest lake in North America. The lake's iconic beauty and abundance of recreational activities generate an estimated $4.7 billion annually.

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The graph below shows volume-averaged temperature in Lake Tahoe 1968-2021. 

• Lake Tahoe water temperatures averaged across multiple depths (volume-averaged) have warmed by approximately 1 degree Fahrenheit (°F) since 1968.
• Surface water temperatures have warmed faster, by about 2°F over the same 50-year period.
• Lake water temperatures and have been warmest in seven of the last ten years, with 2015 being the warmest on record.

• Tracking changes in Lake Tahoe water temperature provides a better understanding of climate effects on high-elevation ecosystems, which are among the fastest-warming globally.

• Even small changes in water temperature affect physical and biological processes in lakes. Rising water temperature prevents the vertical mixing of lake waters, affecting levels of dissolved oxygen and critical nutrients throughout the lake and across the food web.

• Warm temperatures, along with discharges of pollutants into the lake, degrade water quality. Reduced water quality could jeopardize the lake’s attraction as a major tourist destination.

• Increasing water temperatures in Lake Tahoe reflect overall climate trends in the region.
• Lake water temperatures have been rising with warmer air temperatures (particularly in the winter), more rain than snow, declining snowpack, and earlier snowmelt.
• Other factors affecting lake water temperature are ice cover, cloud cover, humidity, and wind. Landscape characteristics such as latitude, elevation, and land cover can modulate climate effects on individual lakes. 

• UC Davis, Tahoe Environmental Research Center, Tahoe: State of the Lake Report 2022