Weather in the Pacific Northwest / Alaska is very unperdictable( I've have lived on the coast for over 50 yrs). One week is sunny and the weeks on either side are wet. In 2005 there were only a few good weeks or even days.
The weather can change daily , hourly or by the minute.
I've seen it where is will rain , snow and be sunny within 5 minutes
Check any weather site a get historical data. July & Aug are usually the best weather .My favorite weather site is "The Weather Underground) link attached