Water Year 2023: Review of a historic year in California and Nevada

Raging muddy water of the Kaweah River in Sequoia National Park, after extremely heavy rains washed soil and debris off slopes burned in a large wildfire.

NPS / Tony Caprio

Water Year (WY) 2023 was truly historic across California and Nevada. The water year is from October 1 through September 30. Two periods of extreme winter precipitation and a rare landfalling tropical storm broke numerous records, ended three years of persistent drought, and revived long-dry Tulare Lake in California’s Central Valley. Temperatures through much of the year were below climatological normal. Notable departures from that trend are July and August, both of which recorded average temperatures in the upper quartile of the historical record across both states. December (2022), January, March, May, June, August, and September posted above average and often top-10 historical statewide precipitation totals for both states. February remained above average in California.

Explore this story map that aims to highlight the antecedent conditions leading into Water Year 2023 as well as the major events and impacts of this remarkable year.

This story map was authored by former Sequoia and Kings Canyon National Parks employee Mike Hittle, who is now a hydrologist with the California-Nevada River Forecast Center, National Weather Service, Sacramento, California.