These Counties Just Had Their Hottest Year Ever

2025 now stands as the third hottest year since record keeping began in 1850. Globally, last year’s average temperature exceeded the pre-industrial annual average by 2.4°F, surpassing nearly every other year, with the exception of 2023 and 2024. Last year’s historically high temperatures were driven in large part by heat-trapping air pollution, a byproduct of fossil fuel consumption – which, despite well-established environmental harms, continues to rise around the world. It is no coincidence each of the 10 hottest years in history were recorded in 2015 or later, according to the independent research organization Climate Central. 

In the United States, 2025 was also a year of near record-breaking heat. According to the National Oceanic and Atmospheric Administration, the average temperature last year was 54.6°F across the Lower 48, exceeding the country’s 20th century average annual temperature by 2.6°F. Ranking as the fourth hottest year in the Continental U.S. since at least 1895, 2025’s average temperature was within a single degree of the 55.5°F all-time high, reported in 2024. 

Still, there were many parts of the country in which last year’s average temperature broke all-time records. In the Southwest climate region – an area comprising Arizona, Colorado, New Mexico, and Utah – the average 2025 temperature was 55.1°F, exceeding the previous record, set in 2017, by a tenth of a degree. Additionally, there were dozens of counties – both in the Southwest and across the country – where 2025 now stands as the hottest year on record. 

Using data from NOAA, Climate Crisis 247 identified the parts of the country where last year’s average temperature hit a record-breaking high. We listed all 10 states home to at least one county where the average annual temperature in 2025 broke historical records. States are ranked by the number of counties reporting all-time annual average highs last year. For each state, we also listed the county where record-breaking 2025 temperatures exceeded the local 20th century average by the greatest amount.

Within the 10 states that rank on this list, the number of counties where average annual temperatures hit an all-time high in 2025 ranges from one to 23. Among these states, which are concentrated west of the Mississippi River, annual temperatures exceeded the 20th century average by anywhere from 2.3°F to 4.3°F in 2025. 

10. Washington

• Counties in Washington with record-high avg. temp. in 2025: 1 of 39 counties in state
• County in Washington with the most abnormally high 2025 avg. temp.: Whitman County
• Avg. 2025 temperature in Whitman County: 52.0°F (4.0°F warmer than local 20th century avg.)
• Avg. 2025 temperature in Washington: 49.1°F – 2nd warmest year on record (3.0°F warmer than statewide 20th century avg.)

9. Idaho

• Counties in Idaho with record-high avg. temp. in 2025: 1 of 44 counties in state
• County in Idaho with the most abnormally high 2025 avg. temp.: Jerome County
• Avg. 2025 temperature in Jerome County: 52.1°F (4.6°F warmer than local 20th century avg.)
• Avg. 2025 temperature in Idaho: 46.0°F – 3rd warmest year on record (3.4°F warmer than statewide 20th century avg.)

8. Texas

• Counties in Texas with record-high avg. temp. in 2025: 3 of 254 counties in state
• County in Texas with the most abnormally high 2025 avg. temp.: Upton County
• Avg. 2025 temperature in Upton County: 68.9°F (4.6°F warmer than local 20th century avg.)
• Avg. 2025 temperature in Texas: 67.7°F – 4th warmest year on record (3.1°F warmer than statewide 20th century avg.)

7. Mississippi

• Counties in Mississippi with record-high avg. temp. in 2025: 4 of 82 counties in state
• County in Mississippi with the most abnormally high 2025 avg. temp.: Holmes County
• Avg. 2025 temperature in Holmes County: 67.5°F (4.1°F warmer than local 20th century avg.)
• Avg. 2025 temperature in Mississippi: 66.0°F – 4th warmest year on record (2.3°F warmer than statewide 20th century avg.)

6. Wyoming

• Counties in Wyoming with record-high avg. temp. in 2025: 4 of 23 counties in state
• County in Wyoming with the most abnormally high 2025 avg. temp.: Sweetwater County
• Avg. 2025 temperature in Sweetwater County: 45.2°F (4.4°F warmer than local 20th century avg.)
• Avg. 2025 temperature in Wyoming: 44.2°F – 3rd warmest year on record (3.5°F warmer than statewide 20th century avg.)

5. New Mexico

• Counties in New Mexico with record-high avg. temp. in 2025: 5 of 33 counties in state
• County in New Mexico with the most abnormally high 2025 avg. temp.: Hidalgo County
• Avg. 2025 temperature in Hidalgo County: 63.4°F (4.5°F warmer than local 20th century avg.)
• Avg. 2025 temperature in New Mexico: 56.2°F – 2nd warmest year on record (3.3°F warmer than statewide 20th century avg.)

4. Colorado

• Counties in Colorado with record-high avg. temp. in 2025: 6 of 64 counties in state
• County in Colorado with the most abnormally high 2025 avg. temp.: Moffat County
• Avg. 2025 temperature in Moffat County: 47.5°F (5.1°F warmer than local 20th century avg.)
• Avg. 2025 temperature in Colorado: 47.8°F – 4th warmest year on record (3.2°F warmer than statewide 20th century avg.)

3. Arizona

• Counties in Arizona with record-high avg. temp. in 2025: 6 of 15 counties in state
• County in Arizona with the most abnormally high 2025 avg. temp.: Pima County
• Avg. 2025 temperature in Pima County: 70.5°F (4.0°F warmer than local 20th century avg.)
• Avg. 2025 temperature in Arizona: 62.9°F – 2nd warmest year on record (3.5°F warmer than statewide 20th century avg.)

2. Nevada

• Counties in Nevada with record-high avg. temp. in 2025: 9 of 17 counties in state
• County in Nevada with the most abnormally high 2025 avg. temp.: Mineral County
• Avg. 2025 temperature in Mineral County: 53.1°F (4.3°F warmer than local 20th century avg.)
• Avg. 2025 temperature in Nevada: 53.2°F – the warmest year on record (3.7°F warmer than statewide 20th century avg.)

1. Utah

• Counties in Utah with record-high avg. temp. in 2025: 23 of 29 counties in state
• County in Utah with the most abnormally high 2025 avg. temp.: Wayne County
• Avg. 2025 temperature in Wayne County: 54.6°F (5.0°F warmer than local 20th century avg.)
• Avg. 2025 temperature in Utah: 51.9°F – the warmest year on record (4.3°F warmer than statewide 20th century avg.)