Monsoon moisture to bring weekend clouds to Central Valley before triple-digit heat
Despite average temperatures early in the month of July, warmer temperatures near 100 degrees are beginning to slide across California and the Central Valley.
That heat will be felt next week, when portions of inland Southern California could rise above 110 degrees. The onset of warmer temperatures will first be marked by phrases of clouds and humidity.
Monsoon moisture moves in soon
Friday is another seasonable day for the Central Valley and Central California with high temperatures in the 90s and low 100s for much of the Central Valley. There is nothing out of the ordinary here — no clouds or moisture will have arrived yet.
.png "temp712).png")
That will not be the case for the days following. Across the western and central United States, another “heat dome” is beginning to take shape. A heat dome is a self-reenforcing mass of high pressure in the upper atmosphere that dominates the sky for thousands of miles. Just as a heat dome brought record-hot temps to the eastern U.S. last week, this heat dome – on our side of the country – will bring hot temps our way.
The heat dome will begin to take shape this weekend, with its center located around Wyoming by Sunday and early next week. Given its location to our northeast, it will drive a warm southeasterly breeze – carrying moisture from the Pacific Ocean – across California and the southwestern U.S.
This is the southwestern monsoon, arriving about a month behind schedule and bringing some clouds, humidity and even rain.
The monsoon’s most immediate effects will be more heavily felt in the southwestern U.S. in places like Las Vegas and Phoenix. But the plume of monsoonal moisture will make a difference for parts of the Central Valley and Sierra this weekend and early next week.
First it will bring some extra clouds and heat. On Saturday, temperatures will rise into the upper 90s for Sacramento and above 100 degrees for the San Joaquin Valley — despite some lighter, higher up clouds set to pass through.
On Sunday, more moisture brings even more clouds. There may even be hours throughout the day when it’s cloudy outside – an anomaly for this time of year. Extra moisture in the San Joaquin Valley for places like Fresno will keep low temperatures above 70 degrees overnight. The air conditioner will get some extra work.
A few light showers are possible across the southern half of the state later Sunday and Monday as the monsoon continues to arrive. This includes for places like Fresno, San Luis Obispo and Los Angeles. Any showers will be brief and isolated, and most folks will not encounter them.
Triple digits temps arrive next week
As the high-pressure heat dome continues to grow, it will work to raise temperatures even further. Highs over 100 degrees are likely for the entire Central Valley early next week – including Sacramento and Modesto. Heat domes can be incredibly stable weather patterns, so expect the hot temperatures to linger next week and possibly even longer.
Portions of inland southern California are under a heat advisory from the National Weather Service this weekend and early next week with temperatures expected to reach up to 112 degrees, including inland San Luis Obispo and Los Angeles counties. More heat advisories are likely to be issued later this weekend for the week to come across the state.
This story was originally published July 10, 2026 at 6:00 AM with the headline "Monsoon moisture to bring weekend clouds to Central Valley before triple-digit heat."
