Excessive Heat Warnings in California
529 excessive heat warnings since 1986. An alert counts here when it covered any part of the state, so the counties below add up to more than the state. The archive of excessive heat warnings reaches back to 2005.
Excessive Heat Warnings by county
Each county as a circle sized by its count since 1986. Tap one for its archive.
- Excessive Heat Warnings
- 529
- Busiest year
- 202161 excessive heat warnings
- Average year
- 28over 19 years on file
Over time
By year
Before late 2005 the archive holds only tornado, severe thunderstorm, flash flood and marine warnings, and from 1997 SPC's watches, so the jump that year is the archive widening, not the weather.
By month of the year
By county
Every county with at least one alert. A county page lists each alert that covered it.
- San Bernardino County198
- Riverside County138
- Inyo County82
- San Diego County77
- Imperial County63
- Los Angeles County53
- Santa Barbara County32
- Santa Clara County19
- Alameda County18
- Contra Costa County18
- Siskiyou County17
- Orange County16
- San Mateo County15
- Monterey County14
- San Benito County13
- Mendocino County13
- Kern County13
- Santa Cruz County12
- Lake County12
- San Luis Obispo County12
- Ventura County12
- Trinity County10
- Fresno County10
- Tulare County10
- Kings County10
- Madera County10
- Mariposa County10
- Merced County10
- Marin County9
- Napa County9
- Sonoma County9
- Humboldt County6
- Modoc County5
- City and County of San Francisco4
- Del Norte County3
- Lassen County3
- Plumas County3
- Sierra County3
Nearby
Sources
National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.