Highest Record-Breaking Temperatures this Summer Were Well Above 100F

So far, 2026 is the hottest year on record in the United States. According to the National Oceanic and Atmospheric Administration, the average temperature between January and August 2026 was 58°F across the Lower 48, higher than the first eight months of any year going back to at least 1895, and 4.1°F hotter than the 20th century average for the same eight month period. This year’s historic temperatures are due in no small part to multiple heatwaves between June and August, which also made this past summer the hottest in U.S. history. 

Across large swaths of the country, temperatures in summer 2026 rose well into the triple digits—in many cases, shattering previous records that had stood for decades. Local weather station data compiled by NOAA shows that new all-time high temperatures were set no less than 120 times between June 1 and August 31, 2026. 

The hottest record-high temperatures of 2026 exceeded 110°F, and were largely concentrated in the West, particularly in Montana, a state where the average year-to-date temperature is 5°F higher than the comparable 20th century average. In parts of Montana, as well as Kansas and Texas, new, triple-digit all-time highs set in 2026 exceed local seasonal norms by more than 20°F. 

Using data from NOAA, Climate Crisis 247 identified the highest record-breaking temperatures in the summer of 2026. We ranked all weather stations with available data on new all-time high temperatures reported between June and August 2026. Only the 10 weather stations with the hottest record-breaking temperatures are listed. All supplemental climate data, including 30-year norms, are from NOAA. County-level population data are five-year estimates from the U.S. Census Bureau’s 2024 American Community Survey. 

10. Cimarron Weather Station, Kansas (Gray County)

• New all-time high local temperature: 113°F on July 28, 2026
• Previous local record high temperature: 111°F on August 17, 1946
• Typical local temperatures in July, 30-year avg.: 92.8°F daily high; 79.8°F daily average
• Gray County population:  5,701

9. Mildred 7 NNW Weather Station, Montana (Prairie County)

• New all-time high local temperature: 113°F on July 13, 2026
• Previous local record high temperature: 110°F on July 15, 2002
• Typical local temperatures in July, 30-year avg.: 87.2°F daily high; 71.4°F daily average
• Prairie County population:  1,250

8. Terry Weather Station, Montana (Prairie County)

• New all-time high local temperature: 113°F on July 13, 2026
• Previous local record high temperature: 111°F on July 15, 2002
• Typical local temperatures in July, 30-year avg.: 88.1°F daily high; 73.3°F daily average
• Prairie County population:  1,250

7. Armells Creek Weather Station, Montana (Fergus County)

• New all-time high local temperature: 113°F on July 12, 2026
• Previous local record high temperature: 108°F on July 24, 2024
• Typical local temperatures in July, 30-year avg.: N/A°F daily high; °F daily average
• Fergus County population:  11,687

6. Brandenberg Weather Station, Montana (Rosebud County)

• New all-time high local temperature: 114°F on July 12, 2026
• Previous local record high temperature: 112°F on July 14, 2002
• Typical local temperatures in July, 30-year avg.: 89.8°F daily high; 72.4°F daily average
• Rosebud County population:  8,165

5. Powderville 8 NNE Weather Station, Montana (Custer County)

• New all-time high local temperature: 114°F on July 12, 2026
• Previous local record high temperature: 110°F on July 27, 2021
• Typical local temperatures in July, 30-year avg.: 90°F daily high; 74.4°F daily average
• Custer County population:  11,961

4. Mizpah 4 NNW Weather Station, Montana (Custer County)

• New all-time high local temperature: 115°F on July 12, 2026
• Previous local record high temperature: 112°F on July 20, 1960
• Typical local temperatures in July, 30-year avg.: 91.3°F daily high; 73.5°F daily average
• Custer County population:  11,961

3. Miles City Airport Weather Station, Montana (Custer County)

• New all-time high local temperature: 115°F on July 12, 2026
• Previous local record high temperature: 111°F on June 26, 2012
• Typical local temperatures in July, 30-year avg.: 88.7°F daily high; 74.2°F daily average
• Custer County population:  11,961

2. Ingomar 9 E Weather Station, Montana (Rosebud County)

• New all-time high local temperature: 116°F on July 13, 2026
• Previous local record high temperature: 112°F on July 14, 2002
• Typical local temperatures in July, 30-year avg.: 88.3°F daily high; 71.6°F daily average
• Rosebud County population:  8,165

1. Cope Ranch Weather Station, Texas (Reagan County)

• New all-time high local temperature: 118°F on June 19, 2026
• Previous local record high temperature: 116°F on June 26, 2023
• Typical local temperatures in June, 30-year avg.: 94.2°F daily high; 79.8°F daily average
• Reagan County population:  3,232