PlainHazard

Heat

NOAA Storm Events type · 35,403 records since 1996 · 51 states and territories

The National Weather Service defines heat as: "A period of heat resulting from the combination of high temperatures (above normal) and relative humidity." NOAA's Storm Events Database holds 35,403 heat records from 1996 through June 30, 2026, the most in Texas (4,750), with 4,046 deaths recorded.

How the National Weather Service files heat

A period of heat resulting from the combination of high temperatures (above normal) and relative humidity. A Heat event occurs and is reported in Storm Data whenever heat index values meet or exceed locally/regionally established advisory thresholds.
National Weather Service Instruction 10-1605, Storm Data Preparation (July 26, 2021), Appendix A, entry 20

Source: National Weather Service Instruction 10-1605. Read the instruction (PDF).

Heat, 1996 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
35,4031996 to June 30, 2026
Deaths
4,04611,093 injuries
Damage, 2025 dollars
$755Mas filed (scale steps before 1993)
Counties with a record
2,289of 3,266

Source: NOAA NCEI Storm Events Database, records through June 30, 2026. Search the record at NCEI.

Where do heat records happen?

States

  1. Texas 4,750
  2. Oklahoma 2,603
  3. Missouri 2,567
  4. Illinois 2,049
  5. Arkansas 1,802
  6. Mississippi 1,789
  7. Tennessee 1,609
  8. Kentucky 1,460
  9. California 1,200
  10. Louisiana 1,197
  11. New York 1,194
  12. New Jersey 1,178
  13. Alabama 1,073
  14. Virginia 1,068
  15. Maryland 1,010

Counties

  1. Maricopa County, AZ 463
  2. Kern County, CA 308
  3. Fresno County, CA 294
  4. Pima County, AZ 266
  5. Tulare County, CA 205
  6. Clark County, NV 179
  7. Kings County, CA 171
  8. Nueces County, TX 164
  9. Madison County, AL 155
  10. Merced County, CA 153

Source: NOAA NCEI Storm Events Database (forecast-zone records count on every county the zone covers).

When do heat records happen?

69% of its heat records since 1996 fell in July and August. The busiest month is July.

The values, month by month

Jan 508 · Feb 508 · Mar 603 · Apr 189 · May 692 · Jun 5,997 · Jul 14,429 · Aug 9,968 · Sep 1,447 · Oct 115 · Nov 352 · Dec 595 (records).

Source: NOAA NCEI Storm Events Database, records by the month they began.

The deadliest heat records

The heat records with the most deaths
DateRecordCharacterKilledInjuredDamage
1999-07-28 HeatCook County, IL · forecast zone Cook An intense heat wave began in the Chicago metropolitan area July 28th and continued through the morning of July 31st. High temperatures on the 28th were in the lower to middle 90s with heat indices 100 to 105. On the 29th the temperatures soared to the middle and upper 90s with heat indices 110 to 120. The heat peaked ... 93 0 –
1999-07-04 HeatPhiladelphia County, PA · forecast zone Philadelphia A very strong and oppressive high pressure system that extended from the surface to aloft gave Eastern Pennsylvania a brutal heat wave that included the entire Independence Day weekend. There were 74 heat related deaths and over 100 reported heat related injuries. High temperatures reached the 90s for the first time ... 58 124 –
2022-06-27 HeatBexar County, TX · forecast zone Bexar Temperatures were unusually hot on the 27th with high temperatures in the San Antonio area ranging from 100-103 degrees (the normal high is 93). Sixty-seven people were found in a tractor-trailer on the southwest side of San Antonio. Fifty-three people died of heat related illnesses. Forty-eight people died at the ... 53 0 –
1999-07-18 HeatSt. Louis (city), MO · forecast zone St. Louis (C) A heat wave gripped the area for the last 2 weeks of July. Temperatures stayed in the middle to upper 90s with a few days topping 100. Columbia set a record high with 104 degrees on 7/29/99. St. Louis tied a record with 103 degrees on 7/30/99. The Heat Index generally ranged from 105 to near 115. Most of the deaths ... 35 142 –
2005-09-21 HeatHarris County, TX · forecast zone Harris Deaths were all associated with the evacuation for Hurricane Rita, both before and after Rita's arrival. Rita made landfall just east of the Texas/Louisiana border early Saturday morning, September 24th. 34 0 –
2006-07-16 HeatFresno County and 3 more, CA · forecast zone E Central S.J. Valley Fresno/Madera/Merced 30 10 $329M
2005-07-12 HeatMaricopa County, AZ · forecast zone Greater Phoenix Area This was the third warmest July on record in Phoenix. The average monthly temperature was 97.3 degrees, just 4 tenths of a degree shy of the record warmest July which was set in 2003. The average maximum temperature for the month was 109.5 compared to a normal of 106.6 degrees. Several daily high temperature records ... 30 0 –
2006-08-01 HeatCook County, IL · forecast zone Cook The second heat wave of the summer developed during late July 2006 and continued into early August. See Stormdata, July 2006, Illinois, Northeast. The high temperature at Northerly Island in downtown Chicago reached 99 on August 1st and 96 on August 2nd. The peak heat reached 115 on August 1st and 114 on August 2nd. ... 24 0 –

Source: NOAA NCEI Storm Events Database, deaths direct and indirect as filed.

The most recent heat records

To June 30, 2026
DateRecordCharacterKilledInjuredDamage
2026-06-30 HeatSt. Francis County, AR · forecast zone St. Francis 0 0 –
2026-06-30 HeatPoinsett County, AR · forecast zone Poinsett 0 0 –
2026-06-30 HeatPhillips County, AR · forecast zone Phillips 0 0 –
2026-06-30 HeatMississippi County, AR · forecast zone Mississippi 0 0 –
2026-06-30 HeatLee County, AR · forecast zone Lee 0 0 –
2026-06-30 HeatGreene County, AR · forecast zone Greene 0 0 –
2026-06-30 HeatCross County, AR · forecast zone Cross 0 0 –
2026-06-30 HeatCrittenden County, AR · forecast zone Crittenden 0 0 –

Source: NOAA NCEI Storm Events Database.

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