Counties in California with the fastest-rising temperatures in the last 100 years
Written by:
January 3, 2023
tradville // Shutterstock
Counties in California with the fastest-rising temperatures in the last 100 years
Hitting 116 degrees F in normally temperate Portland, Oregon. 105 degrees in Reno in September, just as summer is meant to be waning. And in California's Death Valley National Park, temperatures hit almost 130 degrees in the aptly named Furnace Creek, marking a world record for the hottest September day in history.
2021 and 2022 saw some of the hottest temperatures ever recorded, as across the country extreme heat waves wreaked havoc on communities accustomed to more moderate weather. For many regions, the consequences were grave: in the 2021 Western heatwave, hundreds lost their lives, largely due to a lack of air conditioning, and wildfires ravaged the area.
Map of the past year's temperatures compared to the 100-year average
While not every county in the nation has experienced such extreme heat, climate change has dramatically changed the heat landscape in nearly every state. Coastal regions and the Southern U.S. are particularly vulnerable to rising temperatures, and are also frequently targets of extreme weather events like hurricanes and tornadoes.
Just as all states are not impacted equally by rising temperatures, regions within states have also seen widely different temperature changes over the last decades. Factors such as proximity to urban areas, bodies of water, and mountains can dramatically change the climate of a region. Stacker cited data from the National Oceanic and Atmospheric Administration's National Center for Environmental Information to identify the counties in California with the greatest departure from average temperatures during the period December 2021 to November 2022 compared to the 1901-2000 average. Average temperature over the past year served as a tiebreaker. Additional data on recent average high and low temperatures for each county is also included.
#50. Tuolumne County
- Average temperature, Dec. 2021-Nov. 2022: 51.8 degrees Fahrenheit (2.1 F above 1901-2000 average)
- #10 warmest year since 1895
- Recent average low: 39.2 F (2 F above century average)
- Recent average high: 64.4 F (2.3 F above century average)
- #10 warmest year since 1895
- Recent average low: 39.2 F (2 F above century average)
- Recent average high: 64.4 F (2.3 F above century average)
#49. Santa Cruz County
- Average temperature, Dec. 2021-Nov. 2022: 57.8 degrees Fahrenheit (2.1 F above 1901-2000 average)
- #14 warmest year since 1895
- Recent average low: 45.9 F (1.7 F above century average)
- Recent average high: 69.7 F (2.6 F above century average)
- #14 warmest year since 1895
- Recent average low: 45.9 F (1.7 F above century average)
- Recent average high: 69.7 F (2.6 F above century average)
#48. Del Norte County
- Average temperature, Dec. 2021-Nov. 2022: 53 degrees Fahrenheit (2.2 F above 1901-2000 average)
- #10 warmest year since 1895
- Recent average low: 42.6 F (1.1 F above century average)
- Recent average high: 63.5 F (3.2 F above century average)
- #10 warmest year since 1895
- Recent average low: 42.6 F (1.1 F above century average)
- Recent average high: 63.5 F (3.2 F above century average)
#47. Lake County
- Average temperature, Dec. 2021-Nov. 2022: 58.5 degrees Fahrenheit (2.2 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 46.1 F (1.9 F above century average)
- Recent average high: 71 F (2.5 F above century average)
- #7 warmest year since 1895
- Recent average low: 46.1 F (1.9 F above century average)
- Recent average high: 71 F (2.5 F above century average)
#46. Mono County
- Average temperature, Dec. 2021-Nov. 2022: 45.5 degrees Fahrenheit (2.3 F above 1901-2000 average)
- #11 warmest year since 1895
- Recent average low: 31.3 F (2.3 F above century average)
- Recent average high: 59.8 F (2.3 F above century average)
- #11 warmest year since 1895
- Recent average low: 31.3 F (2.3 F above century average)
- Recent average high: 59.8 F (2.3 F above century average)
#45. Nevada County
- Average temperature, Dec. 2021-Nov. 2022: 54 degrees Fahrenheit (2.3 F above 1901-2000 average)
- #9 warmest year since 1895
- Recent average low: 41.6 F (1.9 F above century average)
- Recent average high: 66.4 F (2.6 F above century average)
- #9 warmest year since 1895
- Recent average low: 41.6 F (1.9 F above century average)
- Recent average high: 66.4 F (2.6 F above century average)
#44. Placer County
- Average temperature, Dec. 2021-Nov. 2022: 55.4 degrees Fahrenheit (2.3 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 43.1 F (2.3 F above century average)
- Recent average high: 67.6 F (2.4 F above century average)
- #7 warmest year since 1895
- Recent average low: 43.1 F (2.3 F above century average)
- Recent average high: 67.6 F (2.4 F above century average)
#43. San Mateo County
- Average temperature, Dec. 2021-Nov. 2022: 57.7 degrees Fahrenheit (2.3 F above 1901-2000 average)
- #10 warmest year since 1895
- Recent average low: 47.3 F (1.7 F above century average)
- Recent average high: 68.1 F (2.9 F above century average)
- #10 warmest year since 1895
- Recent average low: 47.3 F (1.7 F above century average)
- Recent average high: 68.1 F (2.9 F above century average)
#42. Alpine County
- Average temperature, Dec. 2021-Nov. 2022: 45.7 degrees Fahrenheit (2.4 F above 1901-2000 average)
- #8 warmest year since 1895
- Recent average low: 34 F (2.3 F above century average)
- Recent average high: 57.4 F (2.5 F above century average)
- #8 warmest year since 1895
- Recent average low: 34 F (2.3 F above century average)
- Recent average high: 57.4 F (2.5 F above century average)
#41. Trinity County
- Average temperature, Dec. 2021-Nov. 2022: 53.9 degrees Fahrenheit (2.4 F above 1901-2000 average)
- #8 warmest year since 1895
- Recent average low: 40.5 F (0.8 F above century average)
- Recent average high: 67.3 F (3.9 F above century average)
- #8 warmest year since 1895
- Recent average low: 40.5 F (0.8 F above century average)
- Recent average high: 67.3 F (3.9 F above century average)
#40. Yolo County
- Average temperature, Dec. 2021-Nov. 2022: 63.3 degrees Fahrenheit (2.4 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 48.8 F (1.3 F above century average)
- Recent average high: 77.7 F (3.5 F above century average)
- #7 warmest year since 1895
- Recent average low: 48.8 F (1.3 F above century average)
- Recent average high: 77.7 F (3.5 F above century average)
#39. El Dorado County
- Average temperature, Dec. 2021-Nov. 2022: 55.8 degrees Fahrenheit (2.5 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 44 F (2.6 F above century average)
- Recent average high: 67.7 F (2.4 F above century average)
- #7 warmest year since 1895
- Recent average low: 44 F (2.6 F above century average)
- Recent average high: 67.7 F (2.4 F above century average)
#38. Mariposa County
- Average temperature, Dec. 2021-Nov. 2022: 57 degrees Fahrenheit (2.5 F above 1901-2000 average)
- #8 warmest year since 1895
- Recent average low: 43.6 F (2.3 F above century average)
- Recent average high: 70.5 F (2.7 F above century average)
- #8 warmest year since 1895
- Recent average low: 43.6 F (2.3 F above century average)
- Recent average high: 70.5 F (2.7 F above century average)
#37. Napa County
- Average temperature, Dec. 2021-Nov. 2022: 60.7 degrees Fahrenheit (2.5 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 47.3 F (1.9 F above century average)
- Recent average high: 74 F (3 F above century average)
- #7 warmest year since 1895
- Recent average low: 47.3 F (1.9 F above century average)
- Recent average high: 74 F (3 F above century average)
#36. Sutter County
- Average temperature, Dec. 2021-Nov. 2022: 64.3 degrees Fahrenheit (2.5 F above 1901-2000 average)
- #5 warmest year since 1895
- Recent average low: 49.6 F (0.9 F above century average)
- Recent average high: 79 F (4.2 F above century average)
- #5 warmest year since 1895
- Recent average low: 49.6 F (0.9 F above century average)
- Recent average high: 79 F (4.2 F above century average)
#35. Shasta County
- Average temperature, Dec. 2021-Nov. 2022: 56.9 degrees Fahrenheit (2.6 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 43.4 F (1.4 F above century average)
- Recent average high: 70.5 F (3.9 F above century average)
- #6 warmest year since 1895
- Recent average low: 43.4 F (1.4 F above century average)
- Recent average high: 70.5 F (3.9 F above century average)
#34. Santa Clara County
- Average temperature, Dec. 2021-Nov. 2022: 59.5 degrees Fahrenheit (2.6 F above 1901-2000 average)
- #11 warmest year since 1895
- Recent average low: 47.4 F (2.2 F above century average)
- Recent average high: 71.5 F (3 F above century average)
- #11 warmest year since 1895
- Recent average low: 47.4 F (2.2 F above century average)
- Recent average high: 71.5 F (3 F above century average)
#33. Monterey County
- Average temperature, Dec. 2021-Nov. 2022: 59.8 degrees Fahrenheit (2.6 F above 1901-2000 average)
- #9 warmest year since 1895
- Recent average low: 45 F (2.3 F above century average)
- Recent average high: 74.5 F (2.9 F above century average)
- #9 warmest year since 1895
- Recent average low: 45 F (2.3 F above century average)
- Recent average high: 74.5 F (2.9 F above century average)
#32. Solano County
- Average temperature, Dec. 2021-Nov. 2022: 62.3 degrees Fahrenheit (2.6 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 49.1 F (1.8 F above century average)
- Recent average high: 75.5 F (3.4 F above century average)
- #7 warmest year since 1895
- Recent average low: 49.1 F (1.8 F above century average)
- Recent average high: 75.5 F (3.4 F above century average)
#31. Colusa County
- Average temperature, Dec. 2021-Nov. 2022: 63 degrees Fahrenheit (2.6 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 48.8 F (1.9 F above century average)
- Recent average high: 77.1 F (3.3 F above century average)
- #6 warmest year since 1895
- Recent average low: 48.8 F (1.9 F above century average)
- Recent average high: 77.1 F (3.3 F above century average)
#30. Sacramento County
- Average temperature, Dec. 2021-Nov. 2022: 63.7 degrees Fahrenheit (2.6 F above 1901-2000 average)
- #5 warmest year since 1895
- Recent average low: 49.7 F (1.5 F above century average)
- Recent average high: 77.7 F (3.8 F above century average)
- #5 warmest year since 1895
- Recent average low: 49.7 F (1.5 F above century average)
- Recent average high: 77.7 F (3.8 F above century average)
#29. Calaveras County
- Average temperature, Dec. 2021-Nov. 2022: 60.4 degrees Fahrenheit (2.7 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 47.4 F (2.6 F above century average)
- Recent average high: 73.2 F (2.9 F above century average)
- #6 warmest year since 1895
- Recent average low: 47.4 F (2.6 F above century average)
- Recent average high: 73.2 F (2.9 F above century average)
#28. Alameda County
- Average temperature, Dec. 2021-Nov. 2022: 60.6 degrees Fahrenheit (2.7 F above 1901-2000 average)
- #5 warmest year since 1895
- Recent average low: 49.5 F (2.4 F above century average)
- Recent average high: 71.6 F (3 F above century average)
- #5 warmest year since 1895
- Recent average low: 49.5 F (2.4 F above century average)
- Recent average high: 71.6 F (3 F above century average)
#27. Glenn County
- Average temperature, Dec. 2021-Nov. 2022: 62 degrees Fahrenheit (2.7 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 48.5 F (1.7 F above century average)
- Recent average high: 75.6 F (3.8 F above century average)
- #6 warmest year since 1895
- Recent average low: 48.5 F (1.7 F above century average)
- Recent average high: 75.6 F (3.8 F above century average)
#26. Inyo County
- Average temperature, Dec. 2021-Nov. 2022: 62.3 degrees Fahrenheit (2.7 F above 1901-2000 average)
- #8 warmest year since 1895
- Recent average low: 49.6 F (3.1 F above century average)
- Recent average high: 75.1 F (2.4 F above century average)
- #8 warmest year since 1895
- Recent average low: 49.6 F (3.1 F above century average)
- Recent average high: 75.1 F (2.4 F above century average)
#25. Siskiyou County
- Average temperature, Dec. 2021-Nov. 2022: 50.6 degrees Fahrenheit (2.8 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 38.2 F (1.8 F above century average)
- Recent average high: 63 F (3.7 F above century average)
- #7 warmest year since 1895
- Recent average low: 38.2 F (1.8 F above century average)
- Recent average high: 63 F (3.7 F above century average)
#24. Tulare County
- Average temperature, Dec. 2021-Nov. 2022: 56 degrees Fahrenheit (2.8 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 43.6 F (3.1 F above century average)
- Recent average high: 68.4 F (2.5 F above century average)
- #6 warmest year since 1895
- Recent average low: 43.6 F (3.1 F above century average)
- Recent average high: 68.4 F (2.5 F above century average)
#23. Madera County
- Average temperature, Dec. 2021-Nov. 2022: 58 degrees Fahrenheit (2.8 F above 1901-2000 average)
- #5 warmest year since 1895
- Recent average low: 44.4 F (2.6 F above century average)
- Recent average high: 71.5 F (3 F above century average)
- #5 warmest year since 1895
- Recent average low: 44.4 F (2.6 F above century average)
- Recent average high: 71.5 F (3 F above century average)
#22. Amador County
- Average temperature, Dec. 2021-Nov. 2022: 60 degrees Fahrenheit (2.8 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 47.3 F (2.6 F above century average)
- Recent average high: 72.8 F (3 F above century average)
- #7 warmest year since 1895
- Recent average low: 47.3 F (2.6 F above century average)
- Recent average high: 72.8 F (3 F above century average)
#21. Tehama County
- Average temperature, Dec. 2021-Nov. 2022: 60.7 degrees Fahrenheit (2.8 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 47.9 F (1.6 F above century average)
- Recent average high: 73.4 F (3.9 F above century average)
- #6 warmest year since 1895
- Recent average low: 47.9 F (1.6 F above century average)
- Recent average high: 73.4 F (3.9 F above century average)
#20. Contra Costa County
- Average temperature, Dec. 2021-Nov. 2022: 61.7 degrees Fahrenheit (2.8 F above 1901-2000 average)
- #5 warmest year since 1895
- Recent average low: 50.2 F (2.6 F above century average)
- Recent average high: 73.1 F (3 F above century average)
- #5 warmest year since 1895
- Recent average low: 50.2 F (2.6 F above century average)
- Recent average high: 73.1 F (3 F above century average)
#19. Stanislaus County
- Average temperature, Dec. 2021-Nov. 2022: 63.1 degrees Fahrenheit (2.8 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 50.2 F (2.3 F above century average)
- Recent average high: 76 F (3.2 F above century average)
- #6 warmest year since 1895
- Recent average low: 50.2 F (2.3 F above century average)
- Recent average high: 76 F (3.2 F above century average)
#18. Merced County
- Average temperature, Dec. 2021-Nov. 2022: 63.8 degrees Fahrenheit (2.8 F above 1901-2000 average)
- #5 warmest year since 1895
- Recent average low: 50.5 F (2.2 F above century average)
- Recent average high: 77 F (3.4 F above century average)
- #5 warmest year since 1895
- Recent average low: 50.5 F (2.2 F above century average)
- Recent average high: 77 F (3.4 F above century average)
#17. Modoc County
- Average temperature, Dec. 2021-Nov. 2022: 48.5 degrees Fahrenheit (2.9 F above 1901-2000 average)
- #8 warmest year since 1895
- Recent average low: 34.6 F (2.2 F above century average)
- Recent average high: 62.4 F (3.7 F above century average)
- #8 warmest year since 1895
- Recent average low: 34.6 F (2.2 F above century average)
- Recent average high: 62.4 F (3.7 F above century average)
#16. Yuba County
- Average temperature, Dec. 2021-Nov. 2022: 62.7 degrees Fahrenheit (2.9 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 49.6 F (2.1 F above century average)
- Recent average high: 75.8 F (3.6 F above century average)
- #6 warmest year since 1895
- Recent average low: 49.6 F (2.1 F above century average)
- Recent average high: 75.8 F (3.6 F above century average)
#15. San Joaquin County
- Average temperature, Dec. 2021-Nov. 2022: 63.6 degrees Fahrenheit (2.9 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 50.4 F (2.2 F above century average)
- Recent average high: 76.9 F (3.6 F above century average)
- #6 warmest year since 1895
- Recent average low: 50.4 F (2.2 F above century average)
- Recent average high: 76.9 F (3.6 F above century average)
#14. San Diego County
- Average temperature, Dec. 2021-Nov. 2022: 64.2 degrees Fahrenheit (2.9 F above 1901-2000 average)
- #8 warmest year since 1895
- Recent average low: 51 F (2.7 F above century average)
- Recent average high: 77.4 F (3.2 F above century average)
- #8 warmest year since 1895
- Recent average low: 51 F (2.7 F above century average)
- Recent average high: 77.4 F (3.2 F above century average)
#13. San Bernardino County
- Average temperature, Dec. 2021-Nov. 2022: 68 degrees Fahrenheit (3 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 55.7 F (3 F above century average)
- Recent average high: 80.4 F (2.9 F above century average)
- #7 warmest year since 1895
- Recent average low: 55.7 F (3 F above century average)
- Recent average high: 80.4 F (2.9 F above century average)
#12. Kern County
- Average temperature, Dec. 2021-Nov. 2022: 63.6 degrees Fahrenheit (3.1 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 50.5 F (3.2 F above century average)
- Recent average high: 76.7 F (3 F above century average)
- #6 warmest year since 1895
- Recent average low: 50.5 F (3.2 F above century average)
- Recent average high: 76.7 F (3 F above century average)
#11. Kings County
- Average temperature, Dec. 2021-Nov. 2022: 65.5 degrees Fahrenheit (3.1 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 51.8 F (2.9 F above century average)
- Recent average high: 79.2 F (3.2 F above century average)
- #7 warmest year since 1895
- Recent average low: 51.8 F (2.9 F above century average)
- Recent average high: 79.2 F (3.2 F above century average)
#10. San Benito County
- Average temperature, Dec. 2021-Nov. 2022: 60.6 degrees Fahrenheit (3.2 F above 1901-2000 average)
- #5 warmest year since 1895
- Recent average low: 47.3 F (3.1 F above century average)
- Recent average high: 73.8 F (3.2 F above century average)
- #5 warmest year since 1895
- Recent average low: 47.3 F (3.1 F above century average)
- Recent average high: 73.8 F (3.2 F above century average)
#9. Butte County
- Average temperature, Dec. 2021-Nov. 2022: 61.9 degrees Fahrenheit (3.2 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 48.6 F (2 F above century average)
- Recent average high: 75.3 F (4.3 F above century average)
- #6 warmest year since 1895
- Recent average low: 48.6 F (2 F above century average)
- Recent average high: 75.3 F (4.3 F above century average)
#8. Imperial County
- Average temperature, Dec. 2021-Nov. 2022: 75.4 degrees Fahrenheit (3.2 F above 1901-2000 average)
- #7 warmest year since 1895
- Recent average low: 61.8 F (3.7 F above century average)
- Recent average high: 89 F (2.7 F above century average)
- #7 warmest year since 1895
- Recent average low: 61.8 F (3.7 F above century average)
- Recent average high: 89 F (2.7 F above century average)
#7. Fresno County
- Average temperature, Dec. 2021-Nov. 2022: 57.7 degrees Fahrenheit (3.3 F above 1901-2000 average)
- #5 warmest year since 1895
- Recent average low: 44.6 F (3.3 F above century average)
- Recent average high: 70.8 F (3.2 F above century average)
- #5 warmest year since 1895
- Recent average low: 44.6 F (3.3 F above century average)
- Recent average high: 70.8 F (3.2 F above century average)
#6. San Luis Obispo County
- Average temperature, Dec. 2021-Nov. 2022: 61.2 degrees Fahrenheit (3.3 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 46.7 F (2.4 F above century average)
- Recent average high: 75.8 F (4.2 F above century average)
- #6 warmest year since 1895
- Recent average low: 46.7 F (2.4 F above century average)
- Recent average high: 75.8 F (4.2 F above century average)
#5. Riverside County
- Average temperature, Dec. 2021-Nov. 2022: 70 degrees Fahrenheit (3.3 F above 1901-2000 average)
- #8 warmest year since 1895
- Recent average low: 57.3 F (3.6 F above century average)
- Recent average high: 82.8 F (2.9 F above century average)
- #8 warmest year since 1895
- Recent average low: 57.3 F (3.6 F above century average)
- Recent average high: 82.8 F (2.9 F above century average)
#4. Santa Barbara County
- Average temperature, Dec. 2021-Nov. 2022: 60.3 degrees Fahrenheit (3.6 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 47.9 F (3.1 F above century average)
- Recent average high: 72.6 F (4.2 F above century average)
- #6 warmest year since 1895
- Recent average low: 47.9 F (3.1 F above century average)
- Recent average high: 72.6 F (4.2 F above century average)
#3. Orange County
- Average temperature, Dec. 2021-Nov. 2022: 65.9 degrees Fahrenheit (3.6 F above 1901-2000 average)
- #6 warmest year since 1895
- Recent average low: 55.5 F (3.7 F above century average)
- Recent average high: 76.4 F (3.5 F above century average)
- #6 warmest year since 1895
- Recent average low: 55.5 F (3.7 F above century average)
- Recent average high: 76.4 F (3.5 F above century average)
#2. Los Angeles County
- Average temperature, Dec. 2021-Nov. 2022: 63.7 degrees Fahrenheit (3.8 F above 1901-2000 average)
- #5 warmest year since 1895
- Recent average low: 51.9 F (3.8 F above century average)
- Recent average high: 75.5 F (3.9 F above century average)
- #5 warmest year since 1895
- Recent average low: 51.9 F (3.8 F above century average)
- Recent average high: 75.5 F (3.9 F above century average)
#1. Ventura County
- Average temperature, Dec. 2021-Nov. 2022: 59.9 degrees Fahrenheit (3.9 F above 1901-2000 average)
- #5 warmest year since 1895
- Recent average low: 47.5 F (3.9 F above century average)
- Recent average high: 72.2 F (3.9 F above century average)
- #5 warmest year since 1895
- Recent average low: 47.5 F (3.9 F above century average)
- Recent average high: 72.2 F (3.9 F above century average)
