How many of you can recall early childhood summer trips to Tahoe and the water being freeeeezing!!? And how many of you have been swimming more recently and found that it is not as bad as you remembered? You haven't gotten tougher; it feels warmer, because temperatures have really changed. Recorded water temperatures at Lake Tahoe have been rising since regular measurements started in the 1960s.

In the last 20 years, through a collaborative project with NASA/JPL, surface water temperatures have been measured on four research buoys in the middle of Lake Tahoe every 2 minutes, and now we know with greater precision the rate at which water temperature is changing.

The warmest month is typically July or August. The graph below shows the average July water temperature (from three feet down) for the last 23 years. This past July 2021 was another record rise, with the highest July average temperature being measured at 68.7 ºF. The actual warmest spot reading was a whopping 72.5 ºF.

Keep Tahoe Cool! 

While these temperatures make for more comfortable swimming conditions, they bring with them potential threats including the creation of conditions that may provide a niche for new invasive species, or existing invasive species to proliferate further. The clarity of Lake Tahoe, the quality of the nearshore environment, and the sustenance of a healthy ecosystem is linked to the temperature of the water. A clearer lake is also a cooler lake, so everything that can be done to restore the clarity of the lake will also help maintain its ecosystems.

Find out more here, or here, or here.

Questions? Email tercinfo@ucdavis.edu