The fire is expected to be 100 percent contained by 6 p.m., said Cal Fire Division Chief David Shew.
He said that firefighters are still working on containing the fire, and while no areas are actively burning, there are "still quite a few hotspots."
He said firefighters are remaining diligent to make sure that no burning embers or wind turn the remaining hotspots into new fires. "We need to get through the heat of the day and the highest wind part of the day," Shew said.
As of last night, the raging fire covered hundreds of acres, and at one point threatened 40 homes. Firefighters prevented any homes or other structures from being burned, however.
"They were successful in going ahead and stopping the forward flow of the fire last night, so that's all been mitigated," Shew said.
The fire was first reported in the area of Torrington Way and Mystic Drive shortly before 6 p.m. Saturday, and it spread to the northeast toward Vacaville.
Cal Fire received support from the Solano County Sheriff's Office, the Vacaville Fire Protection District and other area fire departments. As of 3 p.m. today, all remaining firefighters are from Cal Fire.
The agencies deployed 250 firefighters, 25 fire engines, one helicopter and three bulldozers to tackle the fire.