Hydrology and Climate Data Sources


Streamflow Data

Merced River

The Pohono and Happy Isles gages are located on the main stem of the river in Yosemite Valley. The Wawona gage is on the South Fork of the Merced, near the southern boundary of Yosemite National Park. The Briceburg gage is on Bureau of Land Management land, downstream of the park and downstream of the confluence with the South Fork Merced River.

Tuolumne River

The Grand Canyon of the Tuolumne gage is located just upstream of Hetch Hetchy Reservior, while a second gage is located just downstream of O'Shaughnessy Dam. Data are also available at Falls Creek, a tributary that flows into Hetch Hetchy from the north, and at Tuolumne Meadows, in the Yosemite high country.


Weather Data

Access weather data from stations in Yosemite National Park:

Snow Data

  • Compare this season's Sierra Nevada snow water content [PDF] with the wettest year on record, the driest year on record, the mean value, and last year's value.

  • See snow survey data from the most recent surveys in California. Snow surveys are performed four times per year at 17 courses in Yosemite and many more throughout the West, with records dating back to 1927. Maximum snow depth at one of Yosemite's snow courses was 232.9 inches in 1969; maximum snow water content was 96 inches in 1983. Read the survey's 1953 history in a Yosemite Nature Notes article [600 kb PDF].

  • California Cooperative Snow Survey's real-time data combines data from multiple agencies to monitor seasonal snowpack, forecast snowmelt runoff, and provide a central source of information about snow and water conditions in California. You can also view real-time snow data in the Yosemite area.

Yosemite Observer Dashboard: Physical Sciences


Visual, interactive information about current weather, stream flow, fires, and air quality conditions; all on one site! 


Yosemite Hydrology Videos

These Yosemite-produced videos explore water-related topics:

Resources and Further Reading

Last updated: August 22, 2023

Park footer

Contact Info



Contact Us