Excessive Heat
NOAA Storm Events type · 21,356 records since 2000 · 52 states and territories
The National Weather Service defines excessive heat as: "Excessive Heat results from a combination of high temperatures (well above normal) and high humidity." NOAA's Storm Events Database holds 21,356 excessive heat records from 2000 through June 30, 2026, the most in Oklahoma (2,096), with 2,690 deaths recorded.
How the National Weather Service files excessive heat
Excessive Heat results from a combination of high temperatures (well above normal) and high humidity. An Excessive Heat event occurs and is reported in Storm Data whenever heat index values meet or exceed locally/regionally established excessive heat warning thresholds.
National Weather Service Instruction 10-1605, Storm Data Preparation (July 26, 2021), Appendix A, entry 12
Source: National Weather Service Instruction 10-1605. Read the instruction (PDF).
Excessive Heat, 2000 to 2026
Records per year (2026 to June 30, 2026).
- recorded, no damage figure
- under $10 million
- $10 million or more
- $100 million or more
- $1 billion or more, or 100 deaths
- $10 billion or more, or 1,000 deaths
- a year's colour: its recorded damage or deaths
- a year with a death
- Records
- 21,3562000 to June 30, 2026
- Deaths
- 2,6908,031 injuries
- Damage, 2025 dollars
- $20Mas filed (scale steps before 1993)
- Counties with a record
- 2,237of 3,266
Source: NOAA NCEI Storm Events Database, records through June 30, 2026. Search the record at NCEI.
Where do excessive heat records happen?
States
Counties
Source: NOAA NCEI Storm Events Database (forecast-zone records count on every county the zone covers).
When do excessive heat records happen?
73% of its excessive heat records since 2000 fell in July and August. The busiest month is July.
The values, month by month
Jan 194 · Feb 159 · Mar 120 · Apr 106 · May 316 · Jun 3,870 · Jul 8,415 · Aug 7,159 · Sep 942 · Oct 71 · Nov 2 · Dec 2 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began.
The deadliest excessive heat records
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2023-07-11 | Excessive HeatMaricopa County, AZ · forecast zone Central Phoenix A total of 150 heat-associated fatalities (94 direct and 56 indirect) were reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances, and exact location unavailable. | 150 | 0 | – | |
| 2021-06-26 | Excessive HeatClackamas County and 2 more, OR · forecast zone Greater Portland Metro Area Record breaking temperatures for 3 days in a row. Portland International recorded high temperatures of 108, 112, and 116 F (breaking its previous all time record of 107), and low temperatures of 70, 73, and 75 F. The Oregon State Police and Oregon Medical Examiner reported 67 deaths in Multnomah County from the heat, ... | 93 | 0 | $109K | |
| 2023-07-23 | Excessive HeatMaricopa County, AZ · forecast zone Central Phoenix A total of 46 heat-associated fatalities (17 direct and 29 indirect) were reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances, and exact location unavailable. | 46 | 0 | – | |
| 2020-08-12 | Excessive HeatMaricopa County, AZ · forecast zone Central Phoenix Forty-three heat-associated fatalities were reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances and location unavailable. | 43 | 0 | – | |
| 2024-07-03 | Excessive HeatClark County, NV · forecast zone Las Vegas Valley Excessive Heat Warning criteria were reached on 10 straight days. Forty-two people died in Las Vegas of heat-related causes during and immediately after the heat wave. | 42 | 0 | – | |
| 2023-07-14 | Excessive HeatPima County, AZ · forecast zone Tucson Metro Area Very hot temperatures of 6 to 13 degrees above normal caused the Major Heat Risk category to be reached across eastern Pima County July 14-29. Record highs at Tucson International Airport included 112 degrees on July 20 and 25 (also reached 112 July 18-19); 111 on July 16, 17 and 21; and 110 on the 15th. A total of 40 ... | 40 | 0 | – | |
| 2013-07-01 | Excessive HeatClark County, NV · forecast zone Las Vegas Valley Excessive Heat Warning criteria were reached each day from the 1st through the 4th. Hundreds of people were overcome by the heat. An unusually high mortality rate persisted until July 11th, by which time 39 people had died (including two in June). Another man died in September after being found unresponsive on July ... | 37 | 213 | – | |
| 2023-07-11 | Excessive HeatMaricopa County, AZ · forecast zone East Valley A total of 36 heat-associated fatalities (26 direct and 10 indirect) were reported by the Maricopa County Department of Public Health, with their details, such as age, gender, circumstances, and exact location unavailable. | 36 | 0 | – |
Source: NOAA NCEI Storm Events Database, deaths direct and indirect as filed.
The most recent excessive heat records
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2026-06-30 | Excessive HeatMadison County, IN · forecast zone Madison | 0 | 0 | – | |
| 2026-06-30 | Excessive HeatMidland County, MI · forecast zone Midland | 0 | 0 | – | |
| 2026-06-30 | Excessive HeatSaginaw County, MI · forecast zone Saginaw | 0 | 0 | – | |
| 2026-06-30 | Excessive HeatTuscola County, MI · forecast zone Tuscola | 0 | 0 | – | |
| 2026-06-30 | Excessive HeatHuron County, MI · forecast zone Huron | 0 | 0 | – | |
| 2026-06-30 | Excessive HeatShiawassee County, MI · forecast zone Shiawassee | 0 | 0 | – | |
| 2026-06-30 | Excessive HeatGenesee County, MI · forecast zone Genesee | 0 | 0 | – | |
| 2026-06-30 | Excessive HeatLapeer County, MI · forecast zone Lapeer | 0 | 0 | – |
Source: NOAA NCEI Storm Events Database.