Heat wave will bake much of the Western U.S. over Independence Day 

> “Extreme” heat wave expected in Fresno, California 
 
> Increased risk of wildfires in areas with drought and dry vegetation 

> Air pollution levels could worsen during peak of heat wave   

In the coming days, a surge of intense summer heat will impact seven states in the western United States, increasing the demand for energy and raising the risk of wildfires.  

AccuWeather expert meteorologists say a heat dome will send temperatures skyrocketing this weekend in central California. Record-challenging heat will intensify across parts of the Sacramento Valley and San Joaquin Valley by the middle of next week.  

“Triple-digit heat starts Saturday in Fresno and those high temperatures will continue at least into next weekend,” said AccuWeather Senior Meteorologist Scott Homan. “The forecast high of 115 degrees in Fresno next Saturday would tie the all-time record high from July 8, 1905.”  

An “extreme” heat wave is predicted in Fresno, according to the AccuWeather HeatWave Counter and Severity Index. No heat waves were classified as “extreme” by AccuWeather in 2023 or 2022.  

“Triple-digit heat will bake Bakersfield with high temperatures forecast to be above 105 degrees next Wednesday and Thursday,” said Homan. 

An excessive heat watch will be in effect from July 2 through July 6 for areas of central California.  

 
The surge of heat will intensify by the middle of next week, bringing record-challenging temperatures to parts of California, Arizona, Utah, Nevada, Oregon, and Idaho.  
 

AccuWeather Senior Meteorologist Brett Anderson said the heat will not only be intense during the day, but there will be little relief at night.   

“A significant heat wave may bring both record daily high maximum and minimum temperatures to the West Coast next week,” said Anderson. “Afternoon temperatures will likely surpass the 110-degree mark during the late afternoon across portions of the Central Valley of California from Tuesday through Thursday.” 

Additional strain on the power grid is expected in the western U.S. next weekend, with an increased demand for electricity to run air conditioners and cooling equipment around the clock for homes, businesses, and massive data centers.  

With intense heat expected to impact Independence Day festivities, parades, and family gatherings, Anderson is encouraging people to stay hydrated, wear sunscreen, and to take breaks in shaded areas or air-conditioned buildings to lower the risk of heat-related illnesses.  

“Extreme caution should be taken to protect yourself from the heat and blazing sun next week if you have to be outside for an extended period of time, especially during the afternoon and early evening hours,” said Anderson.  
 
Cities near the coast including Oakland and San Francisco will be spared from the heat wave next week due to the cooling influence from the Pacific waters. 

An area of high-pressure is forecast to further strengthen during the second half of next week and expand northward, which will send extreme heat into the interior valleys of Oregon and Washington from Independence Day through July 6.  
 
AccuWeather is forecasting high temperatures in Medford, Oregon to exceed 100 degrees starting on the 4th of July.  

AccuWeather expert meteorologists say the heat wave and weather pattern in the western U.S. could lead to pockets of poor air quality.  

“Pollutants such as ozone can get trapped by local inversions,” said Anderson.  

An inversion develops when a pocket of warmer air is sitting over top of a pocket of cooler air. Instead of air being able to rise like normal, the air will get trapped underneath the inversion and hovers near the ground. 

Areas of moderate and severe drought across parts of Washington state could worsen next week as hot and dry conditions settle in.  

Anderson said the blockbuster winter storms in California should prevent water supply issues next week.  

“Fortunately for much of California, the reservoirs are in good shape,” said Anderson. “This should not lead to water shortages or restrictions despite the extended period of hot and dry conditions.” 

With hot and dry conditions on Independence Day and over the weekend, AccuWeather expert meteorologists encourage people to use caution with fireworks in areas with drought conditions and dried-out vegetation, in addition to following routine safety guidelines.  

“All you need is a trigger mechanism to spark a fire, whether it’s man-made or the wind,” said AccuWeather Lead Long-Range Forecaster Paul Pastelok. “We are not expecting a ferocious wildfire season, but we do feel there’s going to be more action in comparison to last year. We are expecting more fires and more acreage burned in California, Oregon, and parts of Nevada.” 

More than 2.3 million acres of land have burned across the United States so far this year, according to the National Interagency Fire Center. Wildfire activity has been trending higher this year compared to last year; less than one million acres of land had burned in the U.S. at this point last year.  

California heat wave: Temperatures to top 110 as July begins 
 
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