Extreme Heat Watch
URGENT - WEATHER MESSAGE
National Weather Service San Diego CA
1241 PM PDT Mon Aug 18 2025
CAZ048-190515-
/O.CON.KSGX.XH.A.0002.250821T1700Z-250823T0300Z/
San Bernardino and Riverside County Valleys-The Inland Empire-
Including the cities of Ontario, Rancho Cucamonga, Corona, Moreno
Valley, San Bernardino, Riverside, and Fontana
1241 PM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH REMAINS IN EFFECT FROM THURSDAY MORNING
THROUGH FRIDAY EVENING...
* WHAT...Dangerously hot conditions with high temperatures of 99 to
105 degrees, locally up to 107 degrees, possible and overnight low
temperatures in the low to mid-70s.
* WHERE...San Bernardino and Riverside County Valleys-The Inland
Empire.
* WHEN...From Thursday morning through Friday evening.
* IMPACTS...Heat related illnesses increase significantly during
extreme heat events.
* ADDITIONAL DETAILS...Above average temperatures overnight will
limit overnight relief from the heat. Widespread moderate to
locally major HeatRisk.
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.
Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.
&&
$$
URGENT - WEATHER MESSAGE
National Weather Service San Diego CA
1241 PM PDT Mon Aug 18 2025
CAZ055-056-058-190515-
/O.CON.KSGX.XH.A.0002.250821T1700Z-250823T0300Z/
San Bernardino County Mountains-Riverside County Mountains-San
Diego County Mountains-
Including the cities of Wrightwood, Crestline, Running Springs,
Big Bear City, Lake Arrowhead, Idyllwild-Pine Cove, Julian, Big
Bear Lake, and Pine Valley
1241 PM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH REMAINS IN EFFECT FROM THURSDAY MORNING
THROUGH FRIDAY EVENING...
* WHAT...Dangerously hot conditions with high temperatures of 90 to
100 degrees possible and low temperatures in the upper 60s to
mid-70s.
* WHERE...Riverside County Mountains, San Bernardino County
Mountains, and San Diego County Mountains.
* WHEN...From Thursday morning through Friday evening.
* IMPACTS...Heat related illnesses increase significantly during
extreme heat events.
* ADDITIONAL DETAILS...Above average temperatures overnight will
limit overnight relief from the heat. Widespread moderate to
locally major HeatRisk.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.
Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.
&&
$$
URGENT - WEATHER MESSAGE
National Weather Service San Diego CA
1241 PM PDT Mon Aug 18 2025
CAZ061-062-065-190515-
/O.CON.KSGX.XH.A.0002.250821T1700Z-250823T0300Z/
Coachella Valley-San Diego County Deserts-San Gorgonio Pass near
Banning-
Including the cities of Coachella, La Quinta, Palm Desert
Country, Palm Desert, Indio, Borrego Springs, Cathedral City, and
Palm Springs
1241 PM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH REMAINS IN EFFECT FROM THURSDAY MORNING
THROUGH FRIDAY EVENING...
* WHAT...Dangerously hot conditions with temperatures of 110 to 114
degrees possible with overnight lows in the upper 80s to low 90s.
* WHERE...Coachella Valley, San Diego County Deserts, and San
Gorgonio Pass near Banning.
* WHEN...From Thursday morning through Friday evening.
* IMPACTS...Heat related illnesses increase significantly during
extreme heat events.
* ADDITIONAL DETAILS...There is some uncertainty in high
temperatures with the return of monsoon moisture. However, warm
nights with lows in the upper 80s to low 90s will offer little
relief even if daytime highs are lower due to moisture.
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.
Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.
&&
$$
CO
URGENT - WEATHER MESSAGE
National Weather Service San Diego CA
1241 PM PDT Mon Aug 18 2025
CAZ060-190515-
/O.CON.KSGX.XH.A.0002.250821T1700Z-250823T0300Z/
Apple and Lucerne Valleys-
Including the cities of Victorville, Hesperia, Apple Valley, and
Lucerne Valley
1241 PM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH REMAINS IN EFFECT FROM THURSDAY MORNING
THROUGH FRIDAY EVENING...
* WHAT...Dangerously hot conditions with temperatures up to 106
degrees possible with overnight lows in the mid-70s.
* WHERE...Apple and Lucerne Valleys.
* WHEN...From Thursday morning through Friday evening.
* IMPACTS...Heat related illnesses increase significantly during
extreme heat events.
* ADDITIONAL DETAILS...Above average temperatures overnight will
limit overnight relief from the heat. Widespread major HeatRisk.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.
Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.
&&
$$
URGENT - WEATHER MESSAGE
National Weather Service Hanford CA
1123 AM PDT Mon Aug 18 2025
CAZ300>316-332-190300-
/O.NEW.KHNX.XH.A.0002.250822T1800Z-250824T1500Z/
West Side Mountains north of 198-Los Banos - Dos Palos-Merced -
Madera - Mendota-Planada - Le Grand - Snelling-Coalinga - Avenal-
West Side of Fresno and Kings Counties-Caruthers - San Joaquin -
Selma-Fresno-Clovis-West Side Mountains South of 198-Buttonwillow
- Lost Hills - I5-Delano-Wasco-Shafter-Hanford - Corcoran -
Lemoore-Visalia - Porterville - Reedley-Buena Vista-Bakersfield-
Southeast San Joaquin Valley-South End San Joaquin Valley-Kern
River Valley-
Including the cities of Parlier, Atwater, Sanger, Madera, Lamont,
Kingsburg, Shafter, Lost Hills, Taft, Blackwells Corner, Alpaugh,
McKittrick, Lemoore, Richgrove, Tulare, Fresno, Lemoore Station,
Planada, Los Banos, San Luis Reservoir, Selma, Avenal, Kettleman
City, Wasco, Hanford, Arvin, Lake Isabella, Porterville,
Buttonwillow, Merced, Visalia, Kernville, Le Grand, Kerman,
Delano, Coalinga, Corcoran, Bakersfield, Five Points, Lake
Mcclure, and Goshen
1123 AM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH IN EFFECT FROM FRIDAY MORNING THROUGH SUNDAY
MORNING...
* WHAT...Dangerously hot conditions with high temperatures up to 106
degrees possible. Warm overnight lows around 75 to 80 degrees in
the urban areas from Friday until Sunday morning.
* WHERE...A portion of central California.
* WHEN...From Friday morning through Sunday morning.
* IMPACTS...Heat related illnesses increase significantly during
extreme heat and high humidity events.
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.
Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.
&&
$$
BSO
URGENT - WEATHER MESSAGE
National Weather Service Hanford CA
1123 AM PDT Mon Aug 18 2025
CAZ337>339-190300-
/O.NEW.KHNX.XH.A.0002.250821T1800Z-250824T1500Z/
Indian Wells Valley-Mojave Desert Slopes-Mojave Desert-
Including the cities of Ridgecrest, Edwards AFB, California City,
Inyokern, Randsburg, Rosamond, and Mojave
1123 AM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH IN EFFECT FROM THURSDAY MORNING THROUGH SUNDAY
MORNING...
* WHAT...Dangerously hot conditions with high temperatures 105 to
110 degrees possible. Warm overnight lows in the mid 70s to lower
80s from Thursday until Sunday morning.
* WHERE...Indian Wells Valley, Mojave Desert, and Mojave Desert
Slopes.
* WHEN...From Thursday morning through Sunday morning.
* IMPACTS...Heat related illnesses increase significantly during
extreme heat and high humidity events.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.
Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.
&&
$$
URGENT - WEATHER MESSAGE
National Weather Service Los Angeles/Oxnard CA
1028 AM PDT Mon Aug 18 2025
CAZ352-368-370-190530-
/O.EXB.KLOX.XH.A.0001.250821T2000Z-250823T0400Z/
Santa Ynez Mountains Eastern Range-Los Angeles County Inland
Coast including Downtown Los Angeles-Eastern Santa Monica
Mountains Recreational Area-
Including the cities of Beverly Hills, Downey, Topanga,
Hollywood, Norwalk, Culver City, Montecito Hills, and Compton
1028 AM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH
FRIDAY EVENING...
* WHAT...Dangerously hot conditions with temperatures of 95 to 105
degrees possible.
* WHERE...Eastern Santa Monica Mountains Recreational Area, Los
Angeles County Inland Coast including Downtown Los Angeles, and
Santa Ynez Mountains Eastern Range.
* WHEN...From Thursday afternoon through Friday evening.
* IMPACTS...There is a high risk for dangerous heat illness for
anyone, especially for the very young, the very old, those without
air conditioning, and those active outdoors.
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.
Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.
Monitor the latest forecasts and warnings for updates.
&&
$$
URGENT - WEATHER MESSAGE
National Weather Service Los Angeles/Oxnard CA
1028 AM PDT Mon Aug 18 2025
CAZ369-190530-
/O.EXA.KLOX.XH.A.0001.250820T2000Z-250824T0400Z/
Western Santa Monica Mountains Recreational Area-
Including the cities of Malibu Bowl
1028 AM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH IN EFFECT FROM WEDNESDAY AFTERNOON THROUGH
SATURDAY EVENING...
* WHAT...Dangerously hot conditions with temperatures 95 to 105
degrees possible.
* WHERE...Western Santa Monica Mountains Recreational Area.
* WHEN...From Wednesday afternoon through Saturday evening.
* IMPACTS...There is a high risk for dangerous heat illness for
anyone, especially for the very young, the very old, those without
air conditioning, and those active outdoors.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.
Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.
Monitor the latest forecasts and warnings for updates.
&&
$$
URGENT - WEATHER MESSAGE
National Weather Service Los Angeles/Oxnard CA
1028 AM PDT Mon Aug 18 2025
CAZ088-356>358-371>375-548-190530-
/O.CON.KLOX.XH.A.0001.250820T2000Z-250824T0400Z/
Santa Clarita Valley-Lake Casitas-Ojai Valley-Central Ventura
County Valleys-Calabasas and Agoura Hills-Western San Fernando
Valley-Eastern San Fernando Valley-Southeastern Ventura County
Valleys-Santa Susana Mountains-Los Angeles County San Gabriel
Valley-
Including the cities of Sunland, Oat Mountain, Universal City,
Fillmore, Chatsworth, Woodland Hills, Pomona, Malibu Lake, El
Monte, East Los Angeles, Thousand Oaks, Meiners Oaks, Piru, Oak
View, Northridge, Santa Paula, Glendale, Simi Valley, Newhall,
Santa Clarita, Moorpark, Pasadena, Van Nuys, San Gabriel, Ojai,
La Canada Flintridge, Lake Castaic, Valencia, Newbury Park,
Burbank, and Westlake Village
1028 AM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH REMAINS IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH SATURDAY EVENING...
* WHAT...Dangerously hot conditions with temperatures of 95 to 110
degrees possible.
* WHERE...Calabasas and Agoura Hills, Central Ventura County
Valleys, Eastern San Fernando Valley, Lake Casitas, Los Angeles
County San Gabriel Valley, Ojai Valley, Santa Clarita Valley,
Santa Susana Mountains, Southeastern Ventura County Valleys, and
Western San Fernando Valley.
* WHEN...From Wednesday afternoon through Saturday evening.
* IMPACTS...There is a high risk for dangerous heat illness for
anyone, especially for the very young, the very old, those without
air conditioning, and those active outdoors.
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.
Do not leave young children and pets in unattended vehicles. Car
interiors will reach lethal temperatures in a matter of minutes.
Monitor the latest forecasts and warnings for updates.
&&
$$
URGENT - WEATHER MESSAGE
National Weather Service Los Angeles/Oxnard CA
1028 AM PDT Mon Aug 18 2025
CAZ376>380-190530-
/O.CON.KLOX.XH.A.0001.250820T2000Z-250824T0400Z/
Southern Ventura County Mountains-Northern Ventura County
Mountains-Interstate 5 Corridor-Western San Gabriel Mountains and
Highway 14 Corridor-Eastern San Gabriel Mountains-
Including the cities of Topatopa Mountains, Pyramid Lake, Warm
Springs, Mount Baldy, The Angeles Crest Highway, Mount Pinos,
Ozena, Mill Creek, Wrightwood, Rose Valley, Tejon Pass, Gorman,
Matilija, Acton, Mount Wilson, and Lockwood Valley
1028 AM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH REMAINS IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH SATURDAY EVENING...
* WHAT...Dangerously hot conditions with temperatures of 95 to 110
degrees possible.
* WHERE...Eastern San Gabriel Mountains, Interstate 5 Corridor,
Northern Ventura County Mountains, Southern Ventura County
Mountains, and Western San Gabriel Mountains and Highway 14
Corridor.
* WHEN...From Wednesday afternoon through Saturday evening.
* IMPACTS...There is a high risk for dangerous heat illness for
anyone, especially for the very young, the very old, those without
air conditioning, and those active outdoors.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors.
&&
$$
URGENT - WEATHER MESSAGE
National Weather Service Los Angeles/Oxnard CA
1028 AM PDT Mon Aug 18 2025
CAZ381>383-190530-
/O.CON.KLOX.XH.A.0001.250820T2000Z-250824T0400Z/
Western Antelope Valley Foothills-Eastern Antelope Valley
Foothills-Antelope Valley-
Including the cities of Elizabeth Lake, Pearblossom, Lake
Palmdale, Palmdale, Lancaster, Llano, Lake Los Angeles, and
Valyermo
1028 AM PDT Mon Aug 18 2025
...EXTREME HEAT WATCH REMAINS IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH SATURDAY EVENING...
* WHAT...Dangerously hot conditions with temperatures of 95 to 110
degrees possible.
* WHERE...Antelope Valley, Eastern Antelope Valley Foothills, and
Western Antelope Valley Foothills.
* WHEN...From Wednesday afternoon through Saturday evening.
* IMPACTS...There is a high risk for dangerous heat illness for
anyone, especially for the very young, the very old, those without
air conditioning, and those active outdoors.
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.
&&
$$
Visit us at http://www.weather.gov/LosAngeles
Cohen/Gomberg/Lund/Dumas
URGENT - WEATHER MESSAGE
National Weather Service Flagstaff AZ
522 AM MST Mon Aug 18 2025
AZZ006-191200-
/O.CON.KFGZ.XH.W.0005.250819T1700Z-250821T0300Z/
/O.CON.KFGZ.XH.A.0003.250821T0300Z-250823T0300Z/
Grand Canyon Country-
Including the cities of Supai, North Rim, and Grand Canyon
Village
522 AM MST Mon Aug 18 2025
...EXTREME HEAT WARNING REMAINS IN EFFECT FROM 10 AM TUESDAY TO 8 PM
MST WEDNESDAY BELOW 4000 FEET...
...EXTREME HEAT WATCH REMAINS IN EFFECT FROM WEDNESDAY EVENING
THROUGH FRIDAY EVENING BELOW 4000 FEET...
* WHAT...Dangerously hot conditions expected below 4000 feet, with
daytime temperatures ranging from 102 degrees at Havasupai
Gardens, to 112 degrees at Phantom Ranch.
* WHERE...Lower elevations of the Grand Canyon.
* WHEN...For the Extreme Heat Warning, from 10 AM Tuesday to 8 PM
MST Wednesday. For the Extreme Heat Watch, from Wednesday evening
through Friday evening.
* IMPACTS...Most individuals will be at risk for heat-related
illnesses without effective cooling or adequate hydration,
especially with prolonged outdoor exposure.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
This warning is reserved for only the hottest days of the year and
is issued when temperatures are expected to rise to dangerous levels.
Day hikers on Bright Angel Trail should descend no farther than 1
1/2 miles from the upper trailhead. Between the hours of 10 AM and 4
PM, hikers should be out of the canyon or at Havasupai Gardens or
Bright Angel campgrounds, physical activity is discouraged. All
hikers should have adequate gear, including a wide-brimmed hat,
sunscreen, salty snacks, sufficient water, and electrolyte mix.
Doubling your calorie intake helps maintain your energy.
Hike smart.
Take action when you see symptoms of heat exhaustion and heat
stroke. Anyone overcome by heat should be moved to a cool and shaded
location. Heat stroke is an emergency! Call 9 1 1.
Stay cool, stay hydrated, stay informed.
&&
$$
Humphreys
URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
115 AM MST Mon Aug 18 2025
AZZ530>533-535-536-CAZ560>570-182100-
/O.CON.KPSR.XH.A.0005.250820T1700Z-250823T0300Z/
Parker Valley-Kofa-Yuma-Central La Paz-Southeast Yuma County-Gila
River Valley-Joshua Tree NP West-Joshua Tree NP East-Imperial
County Southwest-Salton Sea-Chuckwalla Mountains-Imperial County
Southeast-Imperial County West-Imperial Valley-Chiriaco Summit-
Palo Verde Valley-Chuckwalla Valley-
Including the cities of Winterhaven, Ripley, Chiriaco Summit,
Palm Canyon, Ligurta, Lost Horse-Keys Village, Yuma, Calexico,
Parker, Cottonwood Visitor, Ocotillo, Palo Verde, Brawley,
Blythe, Harcuvar, Desert Shores, Salome, Coyote Wells, Ehrenberg,
El Centro, Imperial Hot Mineral Springs, Plaster City, Midland,
Vicksburg Junction, Brenda, Alamorio, Winona, Fortuna Foothills,
Mountain Spring, Coolidge Springs, Salton City, Quartzsite,
Martinez Lake, and Vicksburg
115 AM MST Mon Aug 18 2025 /115 AM PDT Mon Aug 18 2025/
...EXTREME HEAT WATCH REMAINS IN EFFECT FROM WEDNESDAY MORNING
THROUGH FRIDAY EVENING...
* WHAT...Dangerously hot conditions possible. Afternoon temperatures
106 to 115. Major Heat Risk.
* WHERE...Portions of southwest Arizona and southeast and southern
California.
* WHEN...From Wednesday morning through Friday evening.
* IMPACTS...Heat related illnesses increase significantly during
extreme heat events. Overexposure can cause heat cramps and heat
exhaustion to develop and, without intervention, can lead to heat
stroke.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
An Extreme Heat Watch means that a period of very hot temperatures,
even by local standards, may occur. Actions should be taken to
lessen the impact of the extreme heat.
Take extra precautions if you work or spend time outside. When
possible, reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose-fitting clothing when possible
and drink plenty of water.
To reduce risk during outdoor work, the Occupational Safety and
Health Administration recommends scheduling frequent rest breaks in
shaded or air conditioned environments. Anyone overcome by heat
should be moved to a cool and shaded location. Heat stroke is an
emergency! Call 9 1 1.
Public cooling shelters are available in some areas. Consult county
officials for more details.
&&
$$
URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
115 AM MST Mon Aug 18 2025
AZZ534-538-539-541-545-547-549-552>556-559-560-562-182100-
/O.CON.KPSR.XH.A.0005.250820T1700Z-250823T0300Z/
Aguila Valley-Tonopah Desert-Gila Bend-Cave Creek/New River-New
River Mesa-Rio Verde/Salt River-Fountain Hills/East Mesa-Superior-
Northwest Pinal County-West Pinal County-Apache Junction/Gold
Canyon-Tonto Basin-Sonoran Desert Natl Monument-San Carlos-
Globe/Miami-
Including the cities of Hassayampa, Tortilla Flat, Cactus Forest,
Aguila, Florence, Kaka, Peridot, Scottsdale, Wintersburg, Globe,
Wickenburg, Coolidge, Superior, Gila Bend, Casa Grande,
Arlington, Miami, San Carlos, Fountain Hills, Apache Junction,
Gladden, Punkin Center, Tonopah, and Sentinel
115 AM MST Mon Aug 18 2025
...EXTREME HEAT WATCH REMAINS IN EFFECT FROM WEDNESDAY MORNING
THROUGH FRIDAY EVENING...
* WHAT...Dangerously hot conditions possible. Afternoon temperatures
106 to 114. Major Heat Risk.
* WHERE...A portion of south central Arizona.
* WHEN...From Wednesday morning through Friday evening.
* IMPACTS...Heat related illnesses increase significantly during
extreme heat events. Overexposure can cause heat cramps and heat
exhaustion to develop and, without intervention, can lead to heat
stroke.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
An Extreme Heat Watch means that a period of very hot temperatures,
even by local standards, may occur. Actions should be taken to
lessen the impact of the extreme heat.
Take extra precautions if you work or spend time outside. When
possible, reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose-fitting clothing when possible
and drink plenty of water.
To reduce risk during outdoor work, the Occupational Safety and
Health Administration recommends scheduling frequent rest breaks in
shaded or air conditioned environments. Anyone overcome by heat
should be moved to a cool and shaded location. Heat stroke is an
emergency! Call 9 1 1.
Public cooling shelters are available in some areas. Consult county
officials for more details.
&&
$$
