Name: Excessive Heat and Heat in Arizona, August 25 to 30, 2023
Start: 2023-08-25T10:00
End: 2023-08-30T20:00
Location: Arizona

Where it happened

Every event with a place to put it; 8 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

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Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
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Open the live radar over this ground

The toll

Deaths: 11
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 8

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS TWC wrote it up.

High pressure aloft strengthened over Arizona and created a period of very hot temperatures August 25-30 across southeast Arizona. High temperatures were 6 to 14 degrees above normal causing the Moderate to Major Heat Risk categories to be reached and numerous high temperature records to be established. A total of eleven heat-related fatalities were reported by the Pima County Medical Examiner.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Tucson, AZ wrote its last area forecast discussion before the first event at Aug 25, 2:32 AM MST, 7 hours 28 minutes earlier.

Area forecast discussion, Aug 25, 2:32 AM MST, 7 hours 28 minutes before

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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

6 excessive heat, 2 heat. Local standard time, as filed.

Heat, Tucson Metro Area

When: August 25, 10:00 AM MST to 8:00 PM MST
Where: Tucson Metro Area forecast zone
Deaths: 0 direct, 1 indirect
Reported by: County Official
Coordinates: 32.097, -111.790 (the zone’s center; the record gives no point)

Hot temperatures around 6 degrees above normal, near 105 degrees, caused the Moderate Heat Risk category to be reached across the Tucson Metro area August 25. The Pima County Medical Examiner determined that heat was a contributing factor in the death of one individual found indoors with a nonfunctioning AC unit. A complicating factor in this fatality was additional health issues.

Excessive Heat, Tohono O Odham Nation

When: August 26, 10:00 AM MST to August 29, 8:00 PM MST
Where: Tohono O Odham Nation forecast zone
Deaths: 2 direct, 0 indirect
Reported by: County Official
Coordinates: 32.501, -111.567 (the zone’s center; the record gives no point)

Very hot temperatures of 7 to 13 degrees above normal caused the Major Heat Risk category to be reached across western Pima County and the Tohono O'odham Nation August 26-29. Record highs at Ajo were 114, 115, 118 and 116 degrees, respectively. Record highs at Organ Pipe Cactus National Monument included 114 degrees on August 28 and 113 on the 29th. Record highs at Sells included 108 degrees on August 26 and 27, and 109 on the 28th. The Pima County Medical Examiner determined that heat was the primary cause of death for two individuals found in the desert on the 26th in the Sells and Topawa areas.

Excessive Heat, Western Pima County

When: August 26, 10:00 AM MST to August 29, 8:00 PM MST
Where: Western Pima County forecast zone
Reported by: Mesonet
Coordinates: 32.097, -111.790 (the zone’s center; the record gives no point)

Very hot temperatures of 7 to 13 degrees above normal caused the Major Heat Risk category to be reached across western Pima County and the Tohono O'odham Nation August 26-29. Record highs at Ajo were 114, 115, 118 and 116 degrees, respectively. Record highs at Organ Pipe Cactus National Monument included 114 degrees on August 28 and 113 on the 29th. Record highs at Sells included 108 degrees on August 26 and 27, and 109 on the 28th. The Pima County Medical Examiner determined that heat was the primary cause of death for two individuals found in the desert on the 26th in the Sells and Topawa areas.

Excessive Heat, Upper Santa Cruz River and Altar Valleys

When: August 27, 10:00 AM MST to August 29, 8:00 PM MST
Where: Upper Santa Cruz River and Altar Valleys forecast zone
Deaths: 2 direct, 0 indirect
Reported by: County Official
Coordinates: 31.812, -111.318 (the zone’s center; the record gives no point)

Very hot temperatures of 7 to 14 degrees above normal caused the Major Heat Risk category to be reached across southeast Pima County, south central Pinal County and the lower elevations of Santa Cruz County August 27-29. Record highs included 111 degrees at Picacho Peak; 108 at Sasabe; and 104 at the Nogales Airport, all on August 29. While not a record, Picacho Peak reached 112 degrees on the 28th. The Pima County Medical Examiner determined that heat was the primary cause of death for two individuals found in the desert of southeast Pima County (one on the 28th about 8 miles southwest of Three Points and one on the 29th just east of the Baboquivari Mountains at 3800 ft near Elkhorn Ranch).

Excessive Heat, South Central Pinal County

When: August 27, 10:00 AM MST to August 29, 8:00 PM MST
Where: South Central Pinal County forecast zone
Reported by: Mesonet
Coordinates: 32.904, -111.345 (the zone’s center; the record gives no point)

Very hot temperatures of 7 to 14 degrees above normal caused the Major Heat Risk category to be reached across southeast Pima County, south central Pinal County and the lower elevations of Santa Cruz County August 27-29. Record highs included 111 degrees at Picacho Peak; 108 at Sasabe; and 104 at the Nogales Airport, all on August 29. While not a record, Picacho Peak reached 112 degrees on the 28th. The Pima County Medical Examiner determined that heat was the primary cause of death for two individuals found in the desert of southeast Pima County (one on the 28th about 8 miles southwest of Three Points and one on the 29th just east of the Baboquivari Mountains at 3800 ft near Elkhorn Ranch).

Excessive Heat, Baboquivari Mountains

When: August 27, 10:00 AM MST to August 29, 8:00 PM MST
Where: Baboquivari Mountains forecast zone
Reported by: Mesonet
Coordinates: 32.097, -111.790 (the zone’s center; the record gives no point)

Very hot temperatures of 7 to 14 degrees above normal caused the Major Heat Risk category to be reached across southeast Pima County, south central Pinal County and the lower elevations of Santa Cruz County August 27-29. Record highs included 111 degrees at Picacho Peak; 108 at Sasabe; and 104 at the Nogales Airport, all on August 29. While not a record, Picacho Peak reached 112 degrees on the 28th. The Pima County Medical Examiner determined that heat was the primary cause of death for two individuals found in the desert of southeast Pima County (one on the 28th about 8 miles southwest of Three Points and one on the 29th just east of the Baboquivari Mountains at 3800 ft near Elkhorn Ranch).

Excessive Heat, Tucson Metro Area

When: August 27, 10:00 AM MST to August 30, 8:00 PM MST
Where: Tucson Metro Area forecast zone
Deaths: 1 direct, 4 indirect
Reported by: County Official
Coordinates: 32.097, -111.790 (the zone’s center; the record gives no point)

Very hot temperatures of 7 to 11 degrees above normal caused the Major Heat Risk category to be reached across eastern Pima County August 27-30. Record highs at Tucson International Airport included 109 degrees on August 28 and 108 on the 29th. The Pima County Medical Examiner determined that heat was the primary cause of death for one individual found indoors on the 28th with a nonfunctioning AC unit in Green Valley where the temperature topped out at 103 degrees. Heat was found to be a contributing factor in the death of four individuals outdoors in Tucson during the period. Two were found outdoors and also experienced a complicating factor of drug toxicity. Three had complicating factors of drug toxicity and one suffered from other health conditions.

Heat, Eastern Cochise County Below 5000 Feet

When: August 28, 10:00 AM MST to 8:00 PM MST
Where: Eastern Cochise County Below 5000 Feet forecast zone
Deaths: 1 direct, 0 indirect
Reported by: County Official
Coordinates: 31.880, -109.751 (the zone’s center; the record gives no point)

Hot temperatures 6 to 8 degrees above normal caused the Moderate Heat Risk category to be reached on August 28 in southeast Cochise County, where temperatures topped out around 100 degrees. The Pima County Medical Examiner determined heat to be the primary cause of death for one individual found in the desert 15 to 20 miles northeast of Douglas.

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

Event	Date	Age	Sex	Where	Kind
Heat, Tucson Metro Area	2023-08-25	64	Female	Permanent Home	Indirect
Excessive Heat, Tohono O Odham Nation	2023-08-26	20	Male	Outside/Open Areas	Direct
Excessive Heat, Tohono O Odham Nation	2023-08-26	36	Male	Outside/Open Areas	Direct
Excessive Heat, Upper Santa Cruz River and Altar Valleys	2023-08-28	20	Female	Outside/Open Areas	Direct
Excessive Heat, Upper Santa Cruz River and Altar Valleys	2023-08-29	20	Female	Outside/Open Areas	Direct
Excessive Heat, Tucson Metro Area	2023-08-28	49	Male	Outside/Open Areas	Indirect
Excessive Heat, Tucson Metro Area	2023-08-29	63	Male	Outside/Open Areas	Indirect
Excessive Heat, Tucson Metro Area	2023-08-29	37	Male	Outside/Open Areas	Indirect
Excessive Heat, Tucson Metro Area	2023-08-30	45	Male	Outside/Open Areas	Indirect
Excessive Heat, Tucson Metro Area	2023-08-28	74	Female	Permanent Home	Direct
Heat, Eastern Cochise County Below 5000 Feet	2023-08-28	37	Male	Outside/Open Areas	Direct

What these are

Heat: Heat below excessive heat criteria that still caused deaths, injuries or significant impacts.
Excessive Heat: Heat at or above the local excessive heat warning criteria, or heat that caused deaths.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Arizona in 2023 Every state in 2023 This day in weather history Warnings in Arizona, August 2023

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1138827, 1138828, 1138829, 1138840, 1138846, 1138848, 1138858, 1138859.