A sweltering heat wave will blanket Southern California through the middle of the week, elevating the fire danger and probably breaking many heat records, according to forecasters.
The National Weather Service on Monday issued an excessive-heat warning through Wednesday, saying the high temperatures will create "a dangerous situation" this week.
The Antelope Valley and other inland valleys are expected to face the worst heat this week, with triple-digit temperatures.
The record books are already being rewritten in places such as Lancaster and Palmdale.
On Sunday, temperatures ranged from the high 70s along the coast and in downtown Los Angeles to 106 in Woodland Hills, 102 in Van Nuys and 116 in Palm Springs.
Records were shattered Monday when temperatures reached 111 in Woodland Hills, 109 in Lancaster, 108 in Palmdale and 104 in Sandberg, according to the weather service. Records in the latter three areas were set in 2008, when temperatures had reached 107 in Lancaster and Palmdale, and 97 in Sandberg.
The Central Valley will be slammed Tuesday as it flirts with a few records.
The National Weather Service is forecasting highs of 108 in Fresno and 109 in Bakersfield.
It has not, been that hot on Aug. 28 in Fresno since Calvin Coolidge was president — it hit 108 in Fresno on that date in 1888 and 1924.
The last time Bakersfield was this hot on Aug. 28 was in 1944, and earlier in 1924.
The Kern High School District canceled or postponed all outdoor and indoor athletic activities because of the extreme heat, the Bakersfield Californian reported.
Meanwhile, Fresno Unified School District coaches were told to use caution with student athletes, the Fresno Bee reported. Coaches were told to offer frequent hydration and shade breaks, and that students shouldn't participate in long-distance running or strenuous conditioning.
At nearby Clovis Unified School District, high school football teams were not allowed to practice in pads or helmets, and shade-water breaks were required every 10 minutes, the newspaper reported.
The National Weather Service said hot and dry conditions will elevate the fire danger in Southern California. The agency's excessive-heat warning was slated to be in effect through Friday night.
"We're still telling people, if they're going to go exercise, do it in the morning — it's the best time. Late evening would be second best," said Kathy Hoxsie, a meteorologist with the weather service.
Some weak sundowner wind conditions will add to the fire danger for the Santa Ynez Mountains in Santa Barbara County through Wednesday, the service said.
"It is critically important to never leave children, elderly people or pets unattended in homes with no air conditioning and particularly in vehicles, even if the windows are 'cracked' or open, as temperatures inside can quickly rise to life-threatening levels," said Jeffrey Gunzenhauser, Los Angeles County's interim health officer.
Times staff writer Alene Tchekmedyian contributed to this report.
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8 p.m.: This article was updated with record-breaking temperatures.