It's considered fire season 12 months out of the year in 2017. Summer and early fall are the worst, but the Washington State Department of Natural Resources is equipped and prepared to deal with fires in the winter.
The current high-pressure system has given the usually wet west side of the mountains almost two weeks of dry, sunny weather, further dried out with winds coming out of the east. One small fire had to be put out in southwest Washington.
Getting onto fires fast is one aspect of the strategy for staying ahead of conditions. We've even had significant fires in January. On New Year's Day in 1995, one fire near Enumclaw burned when it was cold and snowing.
While winter fires are one thing, there are concerns at the peak of Washington's fire season in the late summer. A California style urban fire is considered possible.