The University of California, Davis, Tahoe Environmental Research Center (TERC) released its “Tahoe: State of the Lake Report 2026”, which presents data from 2025 in the context of the long-term record.

The report provides an annual update for non-scientists on the Lake Tahoe Basin’s ecological health. It includes data related to temperature, precipitation and snowmelt, nutrients, algae, water clarity and more.

To learn more about the state of Lake Tahoe and ongoing research and educational outreach efforts, read the full report. 

Lake Tahoe’s famed clarity averaged 69.2 feet in 2025, continuing the encouraging plateau that has followed decades of restoration efforts, according to the State of the Lake Report. 

However, scientists observed unusually high concentrations of tiny, suspended particles in the summer months that may be limiting clarity, despite relatively low inputs from streams and wildfire smoke. Understanding these particles is now a major focus of ongoing research. 

Evidence suggests that microscopic algae, picoplankton, and the tiny diatom Cyclotella may play a much larger role in determining water clarity than previously understood. Understanding these particles has become one of TERC’s highest research priorities.

For nearly 60 years, UC Davis has monitored Lake Tahoe, creating one of the world’s longest records of environmental change. This year’s State of the Lake Report is especially meaningful with the 50th anniversary of the Research Vessel “John LeConte,” which has supported generations of scientific discovery. The report highlights both encouraging signs of progress and the emerging challenges shaping Tahoe’s future, according to a press release. 

Lake Tahoe’s climate continues to warm. Air temperatures are rising, fewer winter days remain below freezing, and spring snowmelt is arriving earlier. These changes influence lake mixing, water temperatures, and the movement of nutrients throughout the ecosystem. While 2025 saw near-average precipitation and a healthy snowpack, the long-term warming trend is evident. 

TERC scientists continue to expand their study of Lake Tahoe with new technologies.

Building on decades of continuous monitoring, researchers are deploying new technologies to study the smallest particles and organisms in the lake, helping answer fundamental questions about clarity, climate change, wildfire impacts, and ecosystem health. These advances will guide future restoration and management efforts. 

A new drone with advanced imaging technology is transforming how researchers monitor algae along the lake’s 75-mile shoreline, providing a much more complete picture than traditional field sampling alone.

Atmospheric nutrients from wildfire smoke returned to near historical averages in 2025 following the elevated levels observed after the Caldor Fire. New analyses also show that smoke from distant wildfires regularly reaches the Tahoe Basin, reinforcing the need to understand how regional fires affect the lake. A new collaboration with atmospheric researchers at UC Davis aims to understand how smoke from fires, near or far, is affecting Lake Tahoe’s freshwater ecosystem, starting with its tiniest inhabitants at the base of the food web. 

The 2026 State of the Lake Report demonstrates that decades of science and restoration have made a difference, while underscoring the challenges posed by climate change, wildfire, and emerging environmental pressures. With one of the world’s longest environmental records and an expanding portfolio of cutting-edge research, UC Davis and its partners are helping ensure that decisions about Lake Tahoe’s future are grounded in the best available science.