Rain and incoming fog may help tame the fires that have killed 20 people and destroyed thousands of homes in California.
Local fire officials said they were hoping for incoming fog expected by the week's end.
Rain and some sleet has also started falling this morning in some parts of the state.
"The good news is that a little too late the weather is changing on us. ... We will still have trouble in the higher elevations, but by Friday we will get higher humidity ... and this will help the fire suppression effort," said Ms Andrea Tuttle, the head of the state's Forestry Department.
There have been 20 confirmed deaths, including two in adjoining areas in Mexico, and a total of 2,427 homes have been destroyed along with 634,000 acres.
California insurance industry officials said claims so far from the fires are likely to reach more than $1 billion in insured losses, making the disaster at least the second most costly wildfire in California history.