SAN FRANCISCO  — Cooler weather helped firefighters gain ground on hundreds of wildfires that charred bone-dry terrain across the heart of wine country and remote forests in Northern California.

One fire had spread across nearly 6 square miles in Napa County and quickly moved into a mostly rural area of Solano County. The fire threatened more than 100 buildings as it fed on grassy woodland about 40 miles southwest of Sacramento, said Roger Archey, a spokesman for the California Department of Forestry and Fire Protection, or Cal Fire.

It was 35 percent contained Sunday evening and had destroyed one home, officials said. Evacuations were ordered for some residents, said agency spokeswoman Nancy Carniglia.

Firefighters in southern New Mexico, meanwhile, were trying to stop a 43,000-acre wildfire — or more than 67 square miles — that’s destroying grazing allotments since starting in the Lincoln National Forest, a U.S. Forest Service fire information officer said.

Two other lightning-sparked wildfires also have burned nearly 30,000 acres — or more than 46 square miles: One was burning west of Roswell in southern New Mexico, and the other was west of Raton in the northern part of the state.

Wildfires have destroyed more than 175 homes in Northern California so far this year. Blazes started popping up in the region just as California’s unofficial fire season began in mid-May, following the state’s driest two-month period on record.

Two blazes about 25 miles south of San Jose also forced several residents from their homes. The fires covered about 2 square miles. Officials said the fires were 50 percent contained on Sunday, and that most residents would be let back into their homes. The fires were also blamed on lightning.

Thunderstorms were responsible for as many as 75 fires in Shasta-Trinity National Forest, about 160 miles north of Sacramento. They ranged in size from less than an acre to more than a square mile. None immediately threatened homes, said Forest Service spokesman Michael Odle.

Mendocino County had as many as 90 fires, charring a total of 5,000 acres, Cal Fire officials said.

South of San Francisco, a fire that started Friday in Santa Cruz County and destroyed homes and closed a stretch of highway was contained after charring just less than a square mile. Evacuation orders were lifted Saturday, a day after roughly 2,000 people fled their homes.

It was the third major blaze to hit Santa Cruz County in the past month. A 520-acre blaze destroyed 11 buildings in the Santa Cruz Mountains, and a fire near Corralitos covered more than 4,200 acres and destroyed about 100 buildings.

Another grass fire in Brisbane, a small city just south of San Francisco, forced evacuations on San Bruno Mountain.