Based on 30 year averages across the entire region - I'm looking at averages of 60-70 degrees (my favorite range!) and the coolest ever 47, and the warmest ever, 80. I've been training in 90. I wear shorts from 50 upwards.
Rain? High 9 days, low 4 and that depends again on the regions. I have my slicker and I did live in Washington State for over a decade and know that I will not melt.