I'm northwest of Mt. Rainier, out by the Sound.
Many years I've looked at the weather report
and seen rain all around me, and looked out
the window to see clear skies and sun overhead
with solid cloud cover at every point of the compass.
Not so lucky this year.
I saw your question in the PNW thread and
replied in more detail there. Synopsis: best bets
would be Sequim or, conditional on having an
effective windbreak, somewhere around the south
end of Indian Heaven
(
http://www.naturenw.org/wild-indian-heaven.htm).
Orcas or Lopez Island might be nice if you have
the funds. Get a greenhouse. This one lady grows
a lot of heirloom tomatoes out on Vashon Island,
farther south, but I haven't seen her setup.
(
http://www.pacificpotager.com/)
So much depends on the specific year. Last year
we had 40 days straight with temperatures pushing
90F, and maybe a week of rain total from the first
of June to the end of August. This year we've had
2-3 good weeks around 80F and one hot one
(1 degree off the record at Sea-Tac). The rest
of the time me might as well have been in St.
Petersburg for the summer.