‘Dangerous heat’ forecast in Northern CA, Central Valley. How long will it last?
Northern California weather is getting a little bit of everything this week, from triple-digit temperatures to a chance of mountain thunderstorms.
While much of Northern California and the Central Valley remains under heat alerts as temperatures climb into the triple digits, forecasters say relief is on the way.
“While hot temperatures continue early this week, a gradual cool down is expected by the middle of the week with a return to seasonable temperatures by the weekend,” the National Weather Service said Monday, June 15, in a post on X.
Until then, "dangerous heat” will continue scorching parts of the region, the weather service said.
Cities including Sacramento, Modesto, Merced and Fresno remain under a heat advisory through 11 p.m. Tuesday, June 16.
Meanwhile, thunderstorms could develop in the mountains later this week, bringing the potential for lightning, gusty winds and brief showers, according to the National Weather Service.
Here’s what to expect in the days ahead:
How long will heat last in Northern California, Central Valley?
According to the National Weather Service, “extreme heat” will impact portions of Northern California and the Central Valley through Tuesday.
Temperatures are expected to climb well above 100 degrees across portions of Northern California and the Central Valley, with some of the hottest conditions expected in the northern Sacramento Valley.
Redding could reach as high as 109 degrees, while Red Bluff is forecast to hit 107 degrees and Chico could top out around 104 degrees.
The heat will also impact Sacramento, Modesto, Merced, Fresno and surrounding foothill communities.
“These hot temperatures combined with low relative humidity and breezy onshore winds, will lead to elevated fire weather conditions in the northern Sacramento Valley and adjacent terrain through Tuesday,” the National Weather Service said.
By Friday, June 19, a “gradual cool down with more seasonable temperatures” are forecast to continue through the weekend.
Thunderstorms, rain forecast across Sierra Nevada
As temperatures begin to ease across the Valley, the Sierra Nevada could see an active weather system.
The National Weather Service is forecasting a chance of mountain showers and thunderstorms on Thursday, June 18, in areas south of Highway 50.
Current forecasts show a 10% to 20% chance of precipitation in portions of the Sierra Nevada, including areas near South Lake Tahoe and Yosemite National Park.
While widespread rainfall is not expected, the National Weather Service said, thunderstorms could bring lightning, brief showers and gusty winds to small areas.
What’s in the weather forecast for Sacramento?
Sacramento is expected to remain hot through the middle of the week before cooler, more seasonable temperatures arrive.
According to the National Weather Service, the current weather forecast for Sacramento shows a high temperature near 95 degrees and a low temperature around 58 degrees on Monday.
Light winds of 5 to 10 mph are expected, with gusts reaching 18 mph.
Tuesday will bring similar conditions, with a high near 93 degrees and a low around 58.
Winds of 5 to 10 mph are forecast, with gusts up to 20 mph.
Wednesday's high is expected to reach 93, while the low will drop to 57.
By Thursday, highs are forecast to fall below 90 degrees and remain that way through the weekend.
How hot will it be in Modesto this week?
The National Weather Service’s current weather forecast for Modesto shows a high temperature near 97 degrees and a low temperature around 65 on Monday, June 15, with light winds of 5 to 8 mph.
Tuesday is expected to be just as hot, with temperatures reaching 97 degrees and overnight lows dipping to around 64. Winds will remain light at 3 to 7 mph.
By Wednesday, highs should cool slightly to around 95 degrees before dropping to about 93 degrees on Thursday.
More relief from the heat arrives Friday, June 19, when temperatures are forecast to fall below 90 degrees.
Heat advisory remains in effect for Merced and Fresno
A heat advisory remains in effect through 11 p.m. Tuesday for much of the San Joaquin Valley, including Merced and Fresno.
“High temperatures up to 102 degrees (are) expected,” the National Weather Service said.
Merced is expected to see its hottest temperatures on Tuesday and Wednesday, with highs nearing 98 degrees before cooling into the 80s by Thursday.
Fresno is forecast to peak around 101 degrees on Tuesday.
While temperatures will gradually decline later in the week, Fresno’s highest temperatures are expected to remain above 90 degrees through Friday before more seasonable conditions arrive over the weekend.
This story was originally published June 15, 2026 at 1:13 PM.
