Cal Fire says about 30 structures are threatened, some of them may be homes.
"It's our duty to save life and property", he said.
"Firefighters have worked throughout the day to establish control lines".
Images on social media showed an eerie yellow smoke over the bay city as the fire continued to burn. No casualties have been reported.
So far this year, wildfires have burned 2.7 million acres in the United States, according to the fire center.
The agency forecast significantly above-normal large fire for July across the U.S. West. The Southwest, which has been struggling with drought, should get enough rain in early July to reduce the risk of major blazes in Arizona, Colorado and New Mexico, the National Interagency Fire Center said Sunday.
A wildfire burning in hot and dry conditions in Utah has forced the evacuation of about seven to 10 seasonal cabins near a popular fishing reservoir.
The blaze, which started at 5:21 p.m. Saturday, had burned 13,700 acres as of 7 a.m. today, up 200 from the same time Wednesday, fire officials said.
Just under a year since the deadliest firestorms in state history, intense wildfire has returned to the region, fanned by high winds and hot temperatures.
The cause of the fire is still under investigation.
A man accused of starting a Colorado wildfire that has destroyed more than 100 homes acknowledged building a fire on land where he has been living but said he made sure it was out, according to a court document.
Mandatory evacuations are in place in Yolo and Napa counties for all areas north of Highway 128, south of County Road 23, east of Berryessa Knoxville Road, and west of County Road 89, according to Cal Fire.
San Juan Basin Public Health on Monday issued an air-quality health advisory throughout La Plata County, as well as areas of Hinsdale, Montezuma and San Juan counties.
The Golf Course Fire was originally estimated to be around 25 acres but infrared equipment Thursday night pinpointed the size at 17.6 acres, Hornbaker said.
In southern Colorado, crews struggled to rein in a wildfire that was spreading in several different directions Sunday.