Name: Excessive Heat in California, July 6 to 7, 2018
Start: 2018-07-06T00:00
End: 2018-07-07T00:00
Location: California

Where it happened

Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 1
Injuries: 50
Property damage: None recorded
Crop damage: None recorded
Events: 4

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 SGX wrote it up.

Strong broad upper level high pressure centered over Nevada and unusual weak offshore flow in July brought extreme hot temperatures and dry conditions to Southern California from July 6th through 8th. Inland Orange County, San Diego Valleys, Inland Empire and the deserts experienced the most extreme temperatures. July 6th was the hottest day during this event, with Thermal and Chino reaching 120 degrees, and San Bernardino and Riverside Airport reaching 118 degrees. July 7th and 8th remained quite hot -- only a few degrees cooler than July 6th. Heat began to subside significantly on July 9th.

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 San Diego, CA wrote its last area forecast discussion before the first event at Jul 5, 8:30 PM PST, 3 hours 30 minutes earlier.

Area forecast discussion, Jul 5, 8:30 PM PST, 3 hours 30 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

4 excessive heat. Local standard time, as filed.

Excessive Heat, San Bernardino and Riverside County Valleys - the Inland Empire

When: July 6, 12:00 AM PST to July 7, 12:00 AM PST
Where: San Bernardino and Riverside County Valleys - the Inland Empire forecast zone
Reported by: ASOS
Coordinates: 34.293, -116.086 (the zone’s center; the record gives no point)

On July 6, temperature at Chino ASOS reached 120F. This is the highest recorded reading for this location and possibly for an ASOS not in the desert. Ontario ASOS reached 117F, the prior highest reading was 114F. Riverside Airport hit 118F and Lake Elsinore reach 119F. On Saturday July 7, the temperatures cooled to 114 at Chino, 113 at Riverside and 112 at Ontario.

Excessive Heat, San Diego County Valleys

When: July 6, 12:00 AM PST to July 7, 12:00 AM PST
Where: San Diego County Valleys forecast zone
Deaths: 1 direct, 0 indirect
Injuries: 50 direct, 0 indirect
Reported by: ASOS
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

Intense heat on July 6 (and offshore flow) resulted in breezy east winds and a high of 117F at Ramona ASOS. The previous record high was 111F. At Escondido the high was 112 and Santee 110, these were just shy of all-time highs. San Diego Public Health and 211 services share statistic which showed a sharp jump in heat related 911 and 211 information calls. 211 San Diego can provide vouchers for those in need of cool shelter during heat waves. The destructive West Fire also occurred in Alpine, San Diego County on July 6. Alpine had highs of 109 and 104 for July 6 and 7th with wind gusts to 30 mph.

Excessive Heat, Orange County Inland

When: July 6, 12:00 AM PST to July 7, 12:00 AM PST
Where: Orange County Inland forecast zone
Reported by: ASOS
Coordinates: 33.677, -117.776 (the zone’s center; the record gives no point)

Santa Ana fire station climate site reached 114F on July 6, this was an all-time high. A scorching 115F was reported at Yorba Linda. On July 7, it still reached 109F at Yorba Linda.

Excessive Heat, Coachella Valley

When: July 6, 12:00 AM PST to July 7, 12:00 AM PST
Where: Coachella Valley forecast zone
Reported by: ASOS
Coordinates: 33.744, -115.994 (the zone’s center; the record gives no point)

Even the desert was hot on July 6, 120F reported at Thermal and 119F at Palm Springs. These were shy of the 123-124F all-time highs. Palm Springs managed to reach 115F the following day.

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
Excessive Heat, San Diego County Valleys	2018-07-06			Unknown	Direct

What these are

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 California in 2018 Every state in 2018 This day in weather history Warnings in California, July 2018

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 2026-09-30. Each event’s entry at NCEI: 783079, 783080, 783082, 783083.