I may get banned for saying this, but I don't know anything Ellensberg.
It's not so much temp's that matter, it's days of sunshine. Like I said before, Seattle doesn'tg get enough sunshine to grow pot outdoors.
To grow good, marijuana needs 3--5 hrs. of direct sushine/dayAn occasional cloudy day is ok.
For seeds for a rookie grow, I suggest using bag seeds--seeds that came with weed you buy.
Otherwise, order some--there's lots of co's to buy them from.
Problem is, it's almost too late to start outdoors. We're past the solstice, the days will be getting shorter all the way until x-mas. You can plant and grow some, but everyday you tarry means less and less final yield.
You need to read up on cultivation, find an area, prep the soil (or use large containers), and use deer deturrents.