A strong upper level high pressure over the southwest US produced well above average temperatures for several days during the first half of August. Most inland areas saw dangerous heat levels with the low elevations of the deserts being particularly affected.
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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.
The episode as NWS SGX wrote it up.
A strong upper level high pressure over the southwest US produced well above average temperatures for several days during the first half of August. Most inland areas saw dangerous heat levels with the low elevations of the deserts being particularly affected. Temperatures peaked on August 7th, a day that produced several record highs across the area.
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 Aug 7, 12:23 PM PST, 2 hours 37 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
123 PM PDT Thu Aug 7 2025
.SYNOPSIS...
Hottest conditions of the week are expected today. There will be a
gradual cooling through the weekend into the middle of next week.
Areas of dense fog are expected tonight into Friday morning on the
coastal mesas. The marine layer is expected to deepen over the
weekend, decreasing the likelihood of dense fog near the coast.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Visible satellite at 1 PM was showing mostly clear skies across the
area with a few patches of low clouds lingering along the immediate
coast. The marine layer is expected to be fairly similar in coverage
and depth tonight into Friday morning. Areas of dense fog are
expected again near coastal mesas early Friday morning.
At 1 PM, most places were running 3 to 5 degrees warmer than
yesterday with some locations in the western valleys closer to 7 or
8 degrees warmer than this time yesterday. High temperatures
today could tie or exceed records for the date for Palm Springs,
Indio, Thermal, and Borrego Springs. For Palm Springs at 1 PM, the
observed temperature was 115 degrees which puts it in good shape
to at least tie and potentially exceed the daily high temperature
record of 116 degrees. Highs on Friday are expected to be 3 to 5
degrees cooler than today for most locations, with continued
cooling into next week. By Saturday, highs will be near to
slightly below normal for the coast and 3 to 6 degrees above
normal for the eastern valleys and deserts. The slow cooling trend
will continue for the next week with high temperatures falling 5
to 10 degrees through Thursday of next week with high temperatures
for next Thursday a few to around 5 degrees below average for the
coast and valleys with the deserts a few degrees above average.
The marine layer will deepen late in the weekend into next week with
night and morning coastal low clouds and fog extending into portions
of the western valleys. There could be some increase in monsoonal
moisture during the middle of next week. NBM chances for thunder for
the mountains and deserts Wednesday and Thursday have decreased to
around 5 percent, down from 10 percent yesterday.
&&
.AVIATION... 072030Z....Coasts...Mostly clear but hazy through the
evening. Areas of low clouds will gradually develop and increase
after 08Z, with best chances of cigs 10-15Z, but will likely not
achieve uniform coverage. Bases will be 400-700 feet MSL with vis
reduced 3-5SM at sea level and 0-2SM on mesas and higher coastal
terrain. Scatter out Friday 15-16Z.
.Valleys/Mountains/Deserts...Hazy but VFR conditions prevail through
Friday.
Smoke from area fires, mostly the Gifford Fire in Santa Barbara
County, will continue to be present at or above 10,000 feet MSL.
Surface conditions hazy but still VFR.
&&
.MARINE...
No hazardous marine conditions are expected through Tuesday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 8 PM PDT Friday for Orange County Inland
Areas-Riverside County Mountains-San Bernardino County
Mountains-San Bernardino and Riverside County Valleys-The
Inland Empire-San Diego County Mountains-San Diego County
Valleys-Santa Ana Mountains and Foothills.
Extreme Heat Warning until 8 PM PDT Friday for Coachella Valley-
San Diego County Deserts-San Gorgonio Pass near Banning.
PZ...None.
&&
PUBLIC...CO
AVIATION/MARINE...MMThe national radar mosaic for the moment the first event began.
4 heat, 1 astronomical low tide. Local standard time, as filed.
Daily record high temperature of 104 at Ramona Airport.
Daily record high temperature of 106 at Campo.
Daily record high temperature of 96 at Idyllwild.
Daily record high temperature of 119 at Palm Springs Regional Airport. Daily record high temperature of 117 at Jaqueline Cochran Regional Airport.
Daily record high temperature of 116 at Borrego Valley Airport.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2025Every state in 2025This day in weather historyWarnings in California, August 2025
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: 1292638, 1292639, 1292640, 1292641, 1292642.