Searing heat wave sets records in California’s inland areas, even as coasts stay cool

October 2020 view of the state Capitol building in Sacramento.
The state Capitol building in Sacramento, where, in like other areas of California, heat advisories have been issued this week.
(Andrew Kleske / San Diego Union-Tribune)

A heat wave swept through California’s Central Valley this week, setting temperature records and prompting heat advisories, even as coastal regions remained temperate.

The thermometer spike from Fresno to Sacramento was spurred by a high-pressure area in the form of a warm dome of air that formed over the Pacific Ocean and pushed inland over the state, according to the National Weather Service.

Triple-digit temperatures in the San Joaquin Valley for the last three days have prompted a heat advisory through at least 8 p.m. Thursday, according to Modesto Vasquez, a meteorologist with the National Weather Service’s Hanford station.


Two small fires broke out earlier this week in foothills north of Fresno, driven in part by the hot, dry conditions and regional drought, Vasquez said.

The excessive heat is expected to continue through Saturday in several areas. On Thursday, Bakersfield has a projected high of 107; Hanford, 104; and Fresno, 103. Highs are expected to drop to around 100 degrees on Saturday.

Nights have also been unseasonably warm. Fresno recorded a record-high nighttime low of 75 degrees on Tuesday, exceeding by four degrees the previous record for the day, Vasquez said.

“It was a warm night,” he said.

Redding, nestled in the north end of the Sacramento Valley, saw a record-high of 109 on Memorial Day, smashing its record of 103 degrees for the date in 2016, according to Cory Mueller, meteorologist with the National Weather Service’s Sacramento station. Sacramento hit 106 that day, tying its record set in 2001.

Temperatures are expected to remain elevated through Saturday, in the mid-90s in the Sacramento area and around 100 in the northern parts of the valley.

However, relief is on the way.

The high pressure area will pass over the state over the next few days and continue east, weather officials said.

A trough of low pressure is expected to follow, gradually driving down temperatures “pretty close to normal” by Monday in the Sacramento area, Mueller said.

No precipitation is expected. “It’ll just bring some cooler temperatures, which I think most people will welcome,” he said.

Vasquez said normal temperatures — in the upper 80s to low 90s — are also expected to return to the San Joaquin Valley by early next week as well.


Coastal regions, including Los Angeles, were spared the temperatures spikes seen in the inland valleys and to the north. Temperatures are expected to remain at typical levels through next week.

A strong onshore flow “is supplying us with much cooler air from the ocean,” said David Sweet, a meteorologist with the National Weather Service’s Oxnard station.

No rain is projected for the next seven days, and rainfall for the year remains at less than half of normal levels, he added.