In some areas of the Bay Area, the weather temperature will begin to dial up a few ticks on Tuesday and then several more again on Wednesday, according to the National Weather Service. Yet even for those areas, the upward movement won’t signal anything larger or hotter in scale.
“As of right now, it’s not looking like we have any massive heat wave anywhere building anytime soon,” NWS meteorologist Matt Mehle said on Tuesday. “It’s going to be cool to mild, really all the way at least into early July.”
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So it goes with a continuous weather pattern that has settled in on the region over the past couple of weeks and that Mehle said shows little sign of changing.
The result so far in the spring of 2025 has been the absence of any long, extended heat wave.
“The big driver of that is that there is an active jet stream that’s is farther south than we usually see at this time,” Mehle said. “So rather than being at a place (in the atmosphere) that allows the high-pressure ridge to build, this jet stream is bringing with it an area for the low pressure to have an effect.”
Within that pattern have been a handful of fluctuations, similar to the one that will push up temperatures in the hottest parts of the region through Wednesday.
For far eastern Contra Costa County cities such as Discovery Bay, Brentwood and Antioch, that means temperatures in the low 90s on Tuesday and the high 90s Wednesday. Brentwood is forecast to peak at 99 degrees and Antioch is expected to reach 97 on Wednesday.
The temperatures elsewhere also will run warm, though not quite to that extent. Livermore and Pleasanton, generally the hottest spots in Alameda County, are expected to peak Wednesday at 90 and 86 degrees, respectively, up about 7 degrees from their forecast high on Tuesday. For cities in the Santa Clara Valley, temperatures are expected to peak at about 86 degrees on Wednesday and about 79 or 80 on Tuesday.
Closer to the coast, it will remain cool. The hotter inland places will go that route on Thursday, Mehle said. Temperatures are expected to fall as much as 20 degrees in the hottest places.
“It’s going to be a pattern change,” he said. “A trough of low pressure will be swinging through from the north, bringing cooler air with it. There will be even more cooling by Friday.”
The cooler to mild weather is expected to stay in place for at least a week and possibly two, according to the weather service’s long-range forecast. It remains unclear at this point whether extreme heat will find its way to the region by the Fourth of July holiday, though Mehle said there’s nothing to indicate a significant change.
“We’re seeing average to normal temperatures all the way out for a couple of weeks,” he said.