Heat Wave Risk in California
All California counties ranked by FEMA National Risk Index heat wave score
Heat Wave risk — prolonged periods of extreme heat that threaten health and infrastructure — is rated for 58 of 58 California counties in FEMA's National Risk Index. Kern County carries the state's highest heat wave score at 99.5, with $43M in expected annual heat wave losses.
17 California counties are rated High or Very High for heat wave, and expected annual losses from heat wave total roughly $378M statewide. The full ranking below links to each county's complete 18-hazard risk profile.
County Rankings — Heat Wave
| # | County | Heat Wave Score | Rating | Ann. Freq. | Ann. Loss |
|---|---|---|---|---|---|
| 1 | Kern County | High | 7.49 / yr | $43M | |
| 2 | Los Angeles County | High | 9.45 / yr | $37M | |
| 3 | Tulare County | High | 5.42 / yr | $30M | |
| 4 | San Diego County | High | 10.25 / yr | $24M | |
| 5 | Santa Clara County | High | 7.98 / yr | $23M | |
| 6 | Riverside County | High | 13.84 / yr | $18M | |
| 7 | San Bernardino County | High | 11.61 / yr | $18M | |
| 8 | Mariposa County | High | 6.05 / yr | $11M | |
| 9 | Contra Costa County | High | 8.49 / yr | $18M | |
| 10 | Fresno County | High | 6.99 / yr | $12M | |
| 11 | Kings County | High | 10.46 / yr | $11M | |
| 12 | Madera County | High | 6.60 / yr | $9M | |
| 13 | Inyo County | High | 10.39 / yr | $9M | |
| 14 | Merced County | High | 10.06 / yr | $10M | |
| 15 | Alameda County | High | 7.10 / yr | $13M | |
| 16 | San Joaquin County | High | 6.98 / yr | $11M | |
| 17 | Orange County | High | 7.41 / yr | $11M | |
| 18 | Stanislaus County | Medium | 7.18 / yr | $8M | |
| 19 | Sacramento County | Medium | 6.97 / yr | $8M | |
| 20 | Monterey County | Medium | 7.46 / yr | $6M | |
| 21 | Imperial County | Medium | 16.90 / yr | $3M | |
| 22 | San Francisco County | Medium | 3.46 / yr | $5M | |
| 23 | San Mateo County | Medium | 4.46 / yr | $4M | |
| 24 | Tuolumne County | Medium | 3.35 / yr | $3M | |
| 25 | Sonoma County | Medium | 7.00 / yr | $3M | |
| 26 | Santa Cruz County | Medium | 5.37 / yr | $3M | |
| 27 | Ventura County | Medium | 9.80 / yr | $2M | |
| 28 | Shasta County | Medium | 5.00 / yr | $2M | |
| 29 | Calaveras County | Medium | 6.10 / yr | $2M | |
| 30 | Butte County | Medium | 6.93 / yr | $1M | |
| 31 | Sutter County | Medium | 7.65 / yr | $1M | |
| 32 | San Luis Obispo County | Low | 8.54 / yr | $2M | |
| 33 | Yolo County | Low | 7.15 / yr | $2M | |
| 34 | Siskiyou County | Low | 5.86 / yr | $991K | |
| 35 | Amador County | Low | 5.89 / yr | $1M | |
| 36 | Solano County | Low | 6.50 / yr | $1M | |
| 37 | Santa Barbara County | Low | 7.29 / yr | $1M | |
| 38 | Glenn County | Low | 7.49 / yr | $1M | |
| 39 | Marin County | Low | 4.53 / yr | $1M | |
| 40 | Placer County | Low | 4.30 / yr | $1M | |
| 41 | El Dorado County | Low | 4.45 / yr | $1M | |
| 42 | Napa County | Low | 7.65 / yr | $794K | |
| 43 | Colusa County | Low | 7.60 / yr | $679K | |
| 44 | San Benito County | Low | 8.22 / yr | $811K | |
| 45 | Nevada County | Low | 4.25 / yr | $517K | |
| 46 | Tehama County | Low | 6.90 / yr | $459K | |
| 47 | Yuba County | Low | 7.51 / yr | $476K | |
| 48 | Lake County | Low | 6.75 / yr | $329K | |
| 49 | Mendocino County | Low | 4.06 / yr | $312K | |
| 50 | Humboldt County | Low | 2.64 / yr | $252K | |
| 51 | Trinity County | Low | 4.85 / yr | $161K | |
| 52 | Modoc County | Very Low | 3.30 / yr | $106K | |
| 53 | Plumas County | Very Low | 2.47 / yr | $76K | |
| 54 | Lassen County | Very Low | 1.80 / yr | $73K | |
| 55 | Mono County | Very Low | 0.53 / yr | $96K | |
| 56 | Del Norte County | Very Low | 1.96 / yr | $31K | |
| 57 | Sierra County | Very Low | 2.28 / yr | $9K | |
| 58 | Alpine County | Very Low | 1.29 / yr | $5K |
58 California counties with measurable heat wave risk. See the national heat wave ranking or all California counties by overall risk.
Frequently Asked Questions
Which California county has the highest heat wave risk?
Kern County has the highest FEMA heat wave risk score in California at 99.5 (High), with $43M in expected annual losses and about 7.49 events per year.
How many California counties face significant heat wave risk?
58 California counties record measurable heat wave risk in FEMA's National Risk Index; 17 of them are rated High or Very High.