According to the National Weather Service, the first few days of fall will bring hot weather to Napa and Sonoma counties.

Residents in both counties can expect temperatures to peak in the mid to high 90s on Monday and Tuesday, with slightly cooler weather returning midweek and into next weekend.

National Weather Service meteorologist Brayden Murdock said the warming weather pattern in the North Bay is not uncommon in September and October. The temperature increase is due to offshore currents creating warmer and drier conditions with less cloud cover and morning fog, he said.

Overnight temperatures are expected to remain cool, with widespread 50-degree temperatures expected statewide, Murdock said.

The highest temperatures recorded in September occurred in Napa and Santa Rosa on Sept. 23, 1939, when temperatures reached highs of 105 and 106 degrees, respectively – the North Bay is not expected to hit again any time soon, Murdock said .

Although Sonoma County will reach temperatures in the 90s, the weather does not meet the criteria for the county to open its cooling centers, according to the County of Sonoma’s Emergency Preparedness, Response and Recovery page.

“Cooling centers have not been discussed at this time, but we are monitoring the situation and may open them if necessary,” said Matt Brown, a spokesman for Sonoma County.

Relief is in sight by Wednesday, Murdock said, as temperatures are expected to temporarily dip back into the mid to high 70s.

Both Napa and Sonoma counties will warm slightly by the end of the week, but not significantly, Murdock said. Temperatures are expected to reach the mid-80s by the weekend.

Contact staff writer Anna Armstrong at 707-521-5255 or [email protected]. On X (Twitter) @annavarmstrongg.