I gather that you’re after morels, which are this region’s signature springtime mushrooms. The actual season depends largely on elevation. If we get some warm weather in February (50s), which is not uncommon, there can be early flushes of mushrooms in March, particularly in areas burned over by forest fire the previous year. The picking starts to accelerate in April at lower elevations, around 1,000 to 2,000 feet, but the main crop comes in May out of the region’s mountains.
You could get lucky if you have a proven spot in mind. Otherwise, speaking from experience, you can spend a lot of time wandering around in the woods, getting poison oak for your pains and coming home empty-handed. Then you’ll walk past a bark-mulched planter bed in the city and see the mushrooms among the shrubbery!
Just make sure wherever you go, you obtain a permit from whatever agency manages the land you’ll be picking on, which can take a bit of figuring out. It’s usually Bureau of Land Management or the U.S. Forest Service.
Here’s a story I wrote for the Mail Tribune newspaper about shrooming that has some more tips.