The authorities in San Diego said they hoped to let some of the 500,000 evacuees start returning home.
But despite the progress, nearly 9,000 firefighters were still waging a pitched battle on hillsides and in canyons while the skies over much of the region were choked with thick, acrid smoke, forcing residents to stay indoors or wear masks.
'We should have almost all of our people back in their homes by this evening,' San Diego Mayor Jerry Sanders said, referring to evacuees within city limits.
California Governor Arnold Schwarzenegger said 18 fires were still burning, threatening 25,000 structures. Nearly 1,500 homes have been destroyed.
San Diego bore the brunt of the damage and officials there put losses in excess of $1bn.
More than half a million people have been forced from their homes in the biggest mass evacuation in modern California history.
Many awaited official permission to return home without knowing the fate of their property or possessions.
At least 412,000 acres of forest and brush have been scorched.
Six deaths have been reported, while 40 people, some of them firefighters, suffered injuries.
The state's Governor, Arnold Schwarzenegger, has requested that the US President declare California a federal disaster zone. George W Bush is to visit the state tomorrow.
Many parts of California have experienced record low rainfalls and record-high temperatures this year, leaving vast swathes of countryside bordering built-up residential areas at the mercy of fires.
'These fires are causing terrible and tragic devastation in our state, but we are responding and we will not stop until everyone is safe,' Mr Schwarzenegger said.
In 2003, 22 people died and more than 3,000 homes were destroyed in wildfires.
