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Excessive Heat Warning — San Bernardino and Riverside County Valleys-The Inland Empire, CA, San Diego County Inland Valleys, CA, Santa Ana Mountains and Foothills, CA, San Diego County Mountains, CA, Apple and Lucerne Valleys, CA, Coachella Valley, CA, San Diego County Deserts, CA, San Gorgonio Pass Near Banning, CA, Orange County Inland, CA, San Diego County Coastal Areas, CA, San Bernardino County Mountains, CA, Riverside County Mountains, CA, Orange County Coastal, CA
Issued
Expires
10:00 PM CDT · Fri, Aug 28 2026
Issuing Office
NWS KSGX

Affected Areas

San Bernardino and Riverside County Valleys-The Inland Empire, CA San Diego County Inland Valleys, CA Santa Ana Mountains and Foothills, CA San Diego County Mountains, CA Apple and Lucerne Valleys, CA Coachella Valley, CA San Diego County Deserts, CA San Gorgonio Pass Near Banning, CA Orange County Inland, CA San Diego County Coastal Areas, CA San Bernardino County Mountains, CA Riverside County Mountains, CA Orange County Coastal, CA

Official Bulletin

140
WWUS76 KSGX 250504
NPWSGX

URGENT - WEATHER MESSAGE
National Weather Service San Diego CA
1004 PM PDT Mon Aug 24 2026

CAZ048-251315-
/O.CON.KSGX.XH.W.0008.260825T1700Z-260829T0300Z/
/O.CON.KSGX.HT.Y.0010.000000T0000Z-260825T1700Z/
San Bernardino and Riverside County Valleys-The Inland Empire-
Including the cities of Riverside, Moreno Valley, Ontario, Fontana,
Corona, Rancho Cucamonga, and San Bernardino
1004 PM PDT Mon Aug 24 2026

...EXTREME HEAT WARNING REMAINS IN EFFECT FROM 10 AM TUESDAY TO 8 PM
PDT FRIDAY...
...HEAT ADVISORY REMAINS IN EFFECT UNTIL 10 AM PDT TUESDAY...

* WHAT...For the Heat Advisory, temperatures up to 106. For the
  Extreme Heat Warning, dangerously hot conditions with temperatures
  up to 110 expected.

* WHERE...San Bernardino and Riverside County Valleys-The Inland
  Empire County.

* WHEN...For the Heat Advisory, until 10 AM PDT Tuesday. For the
  Extreme Heat Warning, from 10 AM Tuesday to 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

* ADDITIONAL DETAILS...Low temperatures 5 to 10 degrees above normal
  will limit relief from the heat. Increasing temperatures into the
  middle of next week will increase the threat of heat-related
  illness across populations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

CAZ050-251315-
/O.CON.KSGX.XH.W.0008.260825T1700Z-260829T0300Z/
/O.CON.KSGX.HT.Y.0010.000000T0000Z-260825T1700Z/
San Diego County Valleys-
Including the cities of San Marcos, Poway, El Cajon, Santee,
Escondido, and La Mesa
1004 PM PDT Mon Aug 24 2026

...EXTREME HEAT WARNING REMAINS IN EFFECT FROM 10 AM TUESDAY TO 8 PM
PDT FRIDAY...
...HEAT ADVISORY REMAINS IN EFFECT UNTIL 10 AM PDT TUESDAY...

* WHAT...For the Heat Advisory, high temperatures in the 90s in the
  western valleys to around 105 in the far inland valleys. For the
  Extreme Heat Warning, dangerously hot conditions with high
  temperatures in he upper 90s to 109 expected.

* WHERE...San Diego County Valleys County.

* WHEN...For the Heat Advisory, until 10 AM PDT Tuesday. For the
  Extreme Heat Warning, from 10 AM Tuesday to 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

* ADDITIONAL DETAILS...Low temperatures 5 to 10 degrees above normal
  will limit relief from the heat. Increasing temperatures into the
  middle of next week will increase the threat of heat-related
  illness across populations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

CAZ057-251315-
/O.CON.KSGX.XH.W.0008.260825T1700Z-260829T0300Z/
/O.CON.KSGX.HT.Y.0010.000000T0000Z-260825T1700Z/
Santa Ana Mountains and Foothills-1004 PM PDT Mon Aug 24 2026

...EXTREME HEAT WARNING REMAINS IN EFFECT FROM 10 AM TUESDAY TO 8 PM
PDT FRIDAY...
...HEAT ADVISORY REMAINS IN EFFECT UNTIL 10 AM PDT TUESDAY...

* WHAT...For the Heat Advisory, high temperatures in the 90s
  expected. For the Extreme Heat Warning, dangerously hot conditions
  with high temperatures in the mid 90s to 105 expected.

* WHERE...Santa Ana Mountains and Foothills County.

* WHEN...For the Heat Advisory, until 10 AM PDT Tuesday. For the
  Extreme Heat Warning, from 10 AM Tuesday to 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

* ADDITIONAL DETAILS...Low temperatures 5 to 10 degrees above normal
  will limit relief from the heat. Increasing temperatures into the
  middle of next week will increase the threat of heat-related
  illness across populations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

CAZ058-251315-
/O.CON.KSGX.XH.W.0008.260825T1700Z-260829T0300Z/
/O.CON.KSGX.HT.Y.0010.000000T0000Z-260825T1700Z/
San Diego County Mountains-
Including the cities of Pine Valley and Julian
1004 PM PDT Mon Aug 24 2026

...EXTREME HEAT WARNING REMAINS IN EFFECT FROM 10 AM TUESDAY TO 8 PM
PDT FRIDAY...
...HEAT ADVISORY REMAINS IN EFFECT UNTIL 10 AM PDT TUESDAY...

* WHAT...For the Heat Advisory, high temperatures in the 90s
  expected. For the Extreme Heat Warning, dangerously hot conditions
  with high temperatures in the mid 90s to 104 expected.

* WHERE...San Diego County Mountains County.

* WHEN...For the Heat Advisory, until 10 AM PDT Tuesday. For the
  Extreme Heat Warning, from 10 AM Tuesday to 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

* ADDITIONAL DETAILS...Low temperatures 5 to 10 degrees above normal
  will limit relief from the heat. Increasing temperatures into the
  middle of next week will increase the threat of heat-related
  illness across populations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

CAZ554-251315-
/O.CON.KSGX.XH.W.0008.260825T1700Z-260829T0300Z/
/O.CON.KSGX.HT.Y.0010.000000T0000Z-260825T1700Z/
Orange County Inland Areas-
Including the cities of Orange, Mission Viejo, Anaheim, Irvine, Santa
Ana, Garden Grove, and Fullerton
1004 PM PDT Mon Aug 24 2026

...EXTREME HEAT WARNING REMAINS IN EFFECT FROM 10 AM TUESDAY TO 8 PM
PDT FRIDAY...
...HEAT ADVISORY REMAINS IN EFFECT UNTIL 10 AM PDT TUESDAY...

* WHAT...For the Heat Advisory, high temperatures in the 90s
  expected. For the Extreme Heat Warning, dangerously hot conditions
  with high temperatures in the mid 90s to 104 expected.

* WHERE...Orange County Inland Areas County.

* WHEN...For the Heat Advisory, until 10 AM PDT Tuesday. For the
  Extreme Heat Warning, from 10 AM Tuesday to 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

* ADDITIONAL DETAILS...Low temperatures 5 to 10 degrees above normal
  will limit relief from the heat. Increasing temperatures into the
  middle of next week will increase the threat of heat-related
  illness across populations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

CAZ061-062-065-251315-
/O.CON.KSGX.XH.W.0008.000000T0000Z-260829T0300Z/
Coachella Valley-San Diego County Deserts-San Gorgonio Pass near
Banning-
Including the cities of Palm Desert Country, Palm Desert, Borrego
Springs, Banning, Desert Hot Springs, La Quinta, Coachella, Cathedral
City, Palm Springs, and Indio
1004 PM PDT Mon Aug 24 2026

...EXTREME HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM PDT FRIDAY...

* WHAT...Dangerously hot conditions with high temperatures of 110 to
  115 expected.

* WHERE...Coachella Valley, San Diego County Deserts, and San
  Gorgonio Pass near Banning Counties.

* WHEN...Until 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

* ADDITIONAL DETAILS...Overnight temperatures 5 to 8 degrees above
  normal will limit relief from the heat.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

CAZ060-251315-
/O.CON.KSGX.XH.W.0008.260825T1700Z-260829T0300Z/
Apple and Lucerne Valleys-
Including the cities of Apple Valley, Victorville, Hesperia, Southern
California Logistics Airport, and Adelanto
1004 PM PDT Mon Aug 24 2026

...EXTREME HEAT WARNING REMAINS IN EFFECT FROM 10 AM TUESDAY TO 8 PM
PDT FRIDAY...

* WHAT...Dangerously hot conditions with high temperatures in the
  upper 90s to 105 expected.

* WHERE...Apple and Lucerne Valleys County.

* WHEN...From 10 AM Tuesday to 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

* ADDITIONAL DETAILS...Low temperatures 5 to 10 degrees above normal
  will limit relief from the heat. Increasing temperatures into the
  middle of next week will increase the threat of heat-related
  illness across populations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

CAZ055-251315-
/O.CON.KSGX.HT.Y.0010.000000T0000Z-260829T0300Z/
San Bernardino County Mountains-
Including the cities of Lake Arrowhead and Crestline
1004 PM PDT Mon Aug 24 2026

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM PDT FRIDAY...

* WHAT...Temperatures in the mid to upper 90s below 5000 ft MSL.

* WHERE...San Bernardino County Mountains below 6000 ft.

* WHEN...Until 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

* ADDITIONAL DETAILS...Low temperatures 5 to 10 degrees above normal
  will limit relief from the heat. Increasing temperatures into the
  middle of next week will increase the threat of heat-related
  illness across populations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

CAZ056-251315-
/O.CON.KSGX.HT.Y.0010.000000T0000Z-260829T0300Z/
Riverside County Mountains-
Including the cities of Idyllwild-Pine Cove
1004 PM PDT Mon Aug 24 2026

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM PDT FRIDAY...

* WHAT...High temperatures in the 90s to low 100s expected.

* WHERE...Riverside County Mountains County.

* WHEN...Until 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

* ADDITIONAL DETAILS...Low temperatures 5 to 10 degrees above normal
  will limit relief from the heat. Increasing temperatures into the
  middle of next week will increase the threat of heat-related
  illness across populations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

CAZ043-251315-
/O.CON.KSGX.HT.Y.0010.260825T1700Z-260829T0300Z/
San Diego County Coastal Areas-
Including the cities of National City, Vista, Carlsbad, Encinitas,
Oceanside, San Diego, and Chula Vista
1004 PM PDT Mon Aug 24 2026

...HEAT ADVISORY REMAINS IN EFFECT FROM 10 AM TUESDAY TO 8 PM PDT
FRIDAY...

* WHAT...High temperatures in the mid 80s near the beaches to the
  lower to mid 90s for the mesas and other higher coastal terrain
  expected.

* WHERE...San Diego County Coastal Areas County.

* WHEN...From 10 AM Tuesday to 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

CAZ552-251315-
/O.CON.KSGX.HT.Y.0010.260825T1700Z-260829T0300Z/
Orange County Coastal Areas-
Including the cities of Costa Mesa and Huntington Beach
1004 PM PDT Mon Aug 24 2026

...HEAT ADVISORY REMAINS IN EFFECT FROM 10 AM TUESDAY TO 8 PM PDT
FRIDAY...

* WHAT...High temperatures in the mid 80s near the beaches to the
  lower to mid 90s for higher coastal terrain expected.

* WHERE...Orange County Coastal Areas County.

* WHEN...From 10 AM Tuesday to 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during
  extreme heat events. Hot temperatures may cause heat illnesses.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.

&&

$$

PS