* More than half of Santa Barbara fire is contained

* Remaining evacuees allowed to return home

SANTA BARBARA, Calif., May 10 (Reuters) - Making the most of cooler, moist weather, firefighters gained an upper hand on Sunday against a stubborn wildfire that has blazed for six days at the edge of Santa Barbara, burning dozens of homes and forcing thousands of residents to flee.

As of Sunday, fire crews had established containment lines around more than half the blaze, which has charred more than 8,700 acres (3,520 hectares) in the foothills above the scenic and largely affluent coastal town 90 miles (145 km) northwest of Los Angeles, authorities told reporters.

Less than a third of the fire had been corralled by late Saturday, after hot, dry, erratic winds abated, giving way to lower temperatures, fog and mist blowing in from the ocean. firefighters also made headway overnight.

With the immediate threat to the city proper averted for the time being, most of the remaining 15,000 evacuees were permitted to return to their homes on Sunday but were advised to remain ready to flee again at a moment's notice.

"We are not out of the woods yet," said Kelly Goethe of the California Department of Forestry and Fire Protection. "One little spark in 50-mph (80-kph) winds and we're right back to where we were a couple of days ago."

He said dangerous "sundowner" winds, which typically gust through mountain passes from the desert after nightfall, could reappear in the next couple of days. For that reason, most of the 4,200 personnel on the fire line would remain in place for the time being.

Some 30,500 people, about a third of Santa Barbara's population, had been under mandatory evacuation orders at the height of the fire threat on Friday.