What to Know
- Temperatures will climb into the 90s Monday, reaching triple-digits in desert areas.
- Fourth of July highs will be around normal for this time of year.
- Air quality alerts were issued until Monday night for inland Orange county and parts of San Bernardino and Riverside counties.
The holiday week starts with excessive heat warnings for parts of Southern California before a slight drop in temperatures for the Fourth of July.
Excessive heat warnings are in effect until 8 p.m. Monday for the high desert, Santa Clarita and Palm Springs. A less severe heat advisory is in effect for San Bernardino, Riverside, parts of northern Los Angeles County and Temecula.
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Temperatures will climb into the 90s Monday across widespread parts of the region before the cooldown for Tuesday's Fourth of July events and gatherings.
"Slightly cooler temperatures will be on tap as we head into the Fourth of July because we can expect a change in the weather pattern," said NBC4 forecaster Stephanie Olmo.
The high-pressure system responsible for the warmer temperatures is expected to begin dissipating later Monday, but temperatures will remain around normal Tuesday.
Here are the high temperatures forecast for Monday/Tuesday.
- Los Angeles basin and inland Orange County: 81/80
- Southern California coast: 70/70
- Valleys: 95/91
- Inland Empire: 96/92
- High Desert: 107/98
- Low Desert: 111/108
- Mountains: 84/78
In the warmest areas, overnight temperatures won't offer much relief with temperatures in the 70 for some areas.
More significant cooling is anticipated Wednesday and Thursday.
The weekend heat arrived after a long stretch of relatively cool temperatures for early summer. Downtown LA reached a high temperature of 80 degrees Sunday, ending a streak of 70 straight days below 80 degrees for the area.
The hot and dry conditions created an elevated wildfire risk. A wildfire burned Monday in Angeles National Forest above Arcadia, growing to about 5 acres. Containment was at 50 percent late Sunday. An evacuation warning was issued for recreational cabins and other buildings in the area.
LA Air Quality Forecast
Air quality alerts were issued until Monday night for inland Orange county and parts of San Bernardino and Riverside counties.
The South Coast Air Quality Management District issued an Ozone Advisory, warning that the excessive heat could increase the likelihood of poor air quality in many areas. Ozone exposure can be hazardous for children, older adults, and people with asthma or COPD.
A map illustrating air quality is available here.
Ozone air pollution can cause respiratory health problems that include trouble breathing, asthma attacks and lung damage.
The agency provided the following tips to help minimize ozone air pollution levels.
Limit the use of gasoline powered lawn and garden equipment until evening hours.
Conserve electricity and set your air conditioner at a higher temperature,
Try to delay trips to the gas station and the use of household chemicals until the evening.
