California heat wave: Temperatures to top 110 as July begins

Record-challenging heat will build over part of California during the first week of the new month, including in Death Valley where the mercury could reach a level rarely achieved.

The start of July will be scorching hot in parts of California as a long-duration heat wave unfolds, sending temperatures past 110 degrees Fahrenheit in the hottest cities.

A heat dome will bring record-challenging heat to many areas of the Sacramento Valley and San Joaquin Valley, starting over the weekend and gradually intensifying throughout the first week of July.

An Excessive Heat Warning has been issued for the Sacramento Valley and San Joaquin Valley, and points just away from the coast from the San Francisco Bay Area through portions of Central California, for Tuesday, July 2, through Saturday, July 6, due to "dangerously hot conditions." This includes Independence Day, a time when many people head outside for holiday festivities.

Additional Excessive Heat Warnings have been issued for interior sections of Southern California, much of southern Nevada and far northwestern Arizona. Many of these warnings begin Wednesday or Thursday and last through late Monday.

Poor air quality is also a concern, as pollutants such as ozone can build up in the stagnant air.

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Not all of California will be affected by the upcoming heat wave, as some of the most densely populated areas will avoid the triple-digit temperatures.

"As you get closer to the coast in cities such as Oakland and San Francisco, the cooling influence from the Pacific waters will remain in place, keeping afternoon temperatures in the much more reasonable 80s," AccuWeather Senior Meteorologist Brett Anderson said.

'Extreme' heat wave likely in Fresno

One of the hottest cities will be Fresno, California, where the mercury could top out at or above the 110-degree mark for several days in a row.

"The forecast high of 115 in Fresno [on] Saturday would tie the all-time record high from July 8, 1905," AccuWeather Senior Meteorologist Scott Homan said.

An "extreme" heat wave is predicted to unfold in Fresno, according to the AccuWeather HeatWave Counter and Severity Index™, which factors in the length and intensity of heat waves and puts them in historical context.

The impending heat wave will be significantly worse than the two heat waves in Fresno in 2023, as well as the heat wave in Sept. 2022, when the temperature climbed above 105 degrees for nine consecutive days.

Death Valley could approach 130 degrees

Death Valley is notorious for its extreme heat, holding the world record for the highest temperature ever recorded at 134 degrees, set on July 10, 1913.

Temperatures could approach 130 degrees near the end of the week, a benchmark seldom reached in the hottest place on Earth.

Since record-keeping began in the early 1900s, the only times when the mercury climbed to 130 were in 1913, 2020 and 2021.

Heat is responsible for more fatalities than any other type of weather across the United States, according to NOAA, and experts urge people in California to take the proper precautions to stay safe.

"Extreme caution should be taken to protect yourself from the heat and blazing sun if you have to be outside for an extended period of time, especially during the afternoon and early-evening hours," Anderson said.