California cold wave risk
San Bernardino County has the highest cold wave risk in California, scoring 28.3 out of 100 — rated "Relatively Low" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | San Bernardino County | 28.3 | Relatively Low |
| 2 | Riverside County | 13.9 | Very Low |
| 3 | Modoc County | 9.7 | Very Low |
| 4 | Ventura County | 8.6 | Very Low |
| 5 | Siskiyou County | 6.6 | Very Low |
| 6 | Los Angeles County | 5.8 | Very Low |
| 7 | Kern County | 3.9 | Very Low |
| 8 | San Diego County | 3.1 | Very Low |
| 9 | Shasta County | 2.7 | Very Low |
| 10 | Lassen County | 2.5 | Very Low |
| 11 | Mono County | 2.4 | Very Low |
| 12 | Inyo County | 2.3 | Very Low |
| 13 | Santa Barbara County | 2.2 | Very Low |
| 14 | Alameda County | 0 | No Rating |
| 15 | Alpine County | 0 | No Rating |
| 16 | Amador County | 0 | No Rating |
| 17 | Butte County | 0 | No Rating |
| 18 | Calaveras County | 0 | No Rating |
| 19 | Colusa County | 0 | No Rating |
| 20 | Contra Costa County | 0 | No Rating |
| 21 | Del Norte County | 0 | No Rating |
| 22 | El Dorado County | 0 | No Rating |
| 23 | Fresno County | 0 | No Rating |
| 24 | Glenn County | 0 | No Rating |
| 25 | Humboldt County | 0 | No Rating |
| 26 | Imperial County | 0 | No Rating |
| 27 | Kings County | 0 | No Rating |
| 28 | Lake County | 0 | No Rating |
| 29 | Madera County | 0 | No Rating |
| 30 | Marin County | 0 | No Rating |
| 31 | Mariposa County | 0 | No Rating |
| 32 | Mendocino County | 0 | No Rating |
| 33 | Merced County | 0 | No Rating |
| 34 | Monterey County | 0 | No Rating |
| 35 | Napa County | 0 | No Rating |
| 36 | Nevada County | 0 | No Rating |
| 37 | Orange County | 0 | No Rating |
| 38 | Placer County | 0 | No Rating |
| 39 | Plumas County | 0 | No Rating |
| 40 | Sacramento County | 0 | No Rating |
| 41 | San Benito County | 0 | No Rating |
| 42 | San Francisco County | 0 | No Rating |
| 43 | San Joaquin County | 0 | No Rating |
| 44 | San Luis Obispo County | 0 | No Rating |
| 45 | San Mateo County | 0 | No Rating |
| 46 | Santa Clara County | 0 | No Rating |
| 47 | Santa Cruz County | 0 | No Rating |
| 48 | Sierra County | 0 | No Rating |
| 49 | Solano County | 0 | No Rating |
| 50 | Sonoma County | 0 | No Rating |
| 51 | Stanislaus County | 0 | No Rating |
| 52 | Sutter County | 0 | No Rating |
| 53 | Tehama County | 0 | No Rating |
| 54 | Trinity County | 0 | No Rating |
| 55 | Tulare County | 0 | No Rating |
| 56 | Tuolumne County | 0 | No Rating |
| 57 | Yolo County | 0 | No Rating |
| 58 | Yuba County | 0 | No Rating |
Source: FEMA National Risk Index v1.20.0, December 2025. Scores are 0–100 percentile rankings among all US counties. See the methodology page for definitions. Download the full CSV for all counties.
Cold Wave risk nationally:
Other hazard risks in California:
Frequently asked questions
What is the highest cold wave risk county in California?
San Bernardino County, CA has the highest cold wave risk in California, with a FEMA National Risk Index score of 28.3 out of 100 (rated "Relatively Low").
What causes cold wave risk in California?
Cold wave risk captures expected losses from extended periods of extreme cold, including wind chill. The northern Plains, Great Lakes, and interior New England see the most severe and frequent cold events. Cold extremes cause significant excess mortality, especially among unhoused populations, the elderly, and those with inadequate heating or insulation. Cold and wind chill events are reported at forecast-zone level in NOAA Storm Events and are not included in county-level counts.