Hot conditions are expected to peak by week's end, and people are doing everything they can to stay cool.
Residents look for ways to stay cool
The Los Angeles beach bus service is an affordable option offered by the county for those looking to beat the heat by heading to the coast.
"It's relaxing if you want to leave all your troubles behind and just go," said Victoria Williams, a Palmdale resident who took a trip down to the beach Tuesday using the beach bus.
The city of Los Angeles is offering extended hours at six cooling centers for the next six days starting Wednesday while county health officials urge people to take care of themselves and others over the next week, especially during the extended 4th of July weekend when holiday plans often mean outdoor activities.
"Me and my family are trying to do something indoor then going to see the fireworks at night because it's too hot to be outside," said Tarzana resident Eva Menjivar.
What to expect from this week's heat wave in SoCal
An excessive heat warning will be in effect until 6 p.m. Monday for the 5 and 15 freeway corridors, the western San Gabriel Mountains, the Antelope Valley foothills and the Antelope Valley, according to the National Weather Service.
Temperatures in the warning area could reach as high as 115 degrees, forecasters said.
An excessive heat warning will take effect at 11 a.m. Wednesday and continue through 6 p.m. Monday in the Santa Clarita Valley, the Santa Monica Mountains Recreational Area, Calabasas, San Fernando Valley and eastern San Gabriel Mountains, where temperatures up to 110 degrees are possible.
The San Gabriel Valley will be under a less severe heat advisory from 11 a.m. Wednesday through 6 p.m. Sunday, but temperatures there are still expected to reach as high as 105.
The Los Angeles coastal area stretching into downtown will be under a heat advisory from 11 a.m. Thursday through 6 p.m. Sunday, with temperatures topping out at 85 to 95 degrees.
The high temperatures and low humidity will also create an extended period of elevated to critical fire danger in areas away from the coast, forecasters said.
A fire weather watch will be in place from Thursday evening through Friday night in the western Antelope Valley foothills and the 5 Freeway corridor, where forecasters said the hot and dry conditions will be joined by northwest winds potentially gusting from 25 to 40 mph.
"A significant heatwave will impact the region this week through early next week, with dangerously hot temperatures across much of the area,'' according to the NWS. "High temperatures by mid to late week are expected to reach 95 to 105 degrees in many areas away from the coast, with highs upwards of 105 to 115 over interior valleys and foothills, including the Antelope Valley. Very warm to hot conditions could extend closer to the coast by late this week.''
The heat was building thanks to a large upper high-pressure system moving in from the west. As the system settles in, most areas will see another 3 to 6 degrees of warming on Wednesday, then another 4 to 8 degrees in coastal and valley areas on Thursday. Valley and inland areas will likely have temperatures that are 10 to 15 degrees above normal by Thursday, according to the NWS.
Friday is expected to be the hottest day of the week, with temperatures rising another 2 to 4 degrees, meaning highs of 110 to 115 in interior areas, 100 to 105 in the valleys, 90s along interior coastal areas and 80s at the beaches.
Those temperatures are 6 to 12 degrees above normal for the coasts, and 12 to 18 degrees above normal for the valleys and interior areas.
Forecasters said "only minimal cooling'' is expected over the weekend, along increasing onshore flow should eventually cool things down along the coasts and slowly move into the valleys. But the high-pressure system is expected to persist, and the heat wave "may push deep into next week,'' according to the NWS.
"The combination of these very hot temperatures, areas of low humidities and possible sundowner winds will lead to fire weather risks,'' forecasters said.
In Orange County, a heat advisory will be in effect for the Santa Ana Mountains and foothills and Orange County inland areas from 11 a.m. Friday through 9 p.m. Saturday, with temperatures at or near triple-digit levels.
Authorities reminded the public to never leave pets or children inside vehicles on days that are even a little warmer than normal, as locked cars can turn into death traps in mere minutes.
The city and county of Los Angeles both operate cooling centers for people who need a place to escape the heat. To find a location, visit https://ready.lacounty.gov/heat/ or call 211.
City News Service, Inc. contributed to this report.