RT-
The SW Washington streams all tend to have openings in May because they have always had strong returns of native springer steelhead, but sadly those fish are gone. But because they are heavly planted in Skamania strains they can support May fisheries.

The NF Stilly is also open in May, for the bug rod only but she will not open up 'till June 1st due to the Puget Sound river closures. I am going to severely miss the Stilly next month!!

Everythng else except some of the very lower sections of rivers open up June 1. Some of the lower sections of the Skagit, Snohomish, etc. are open year-round.