Today several locations in western Washington reached in the low 60s....in fact some surged into the mid-60s. Offshore flow helped....as air descended down the western slopes of the Cascades it it is compressed and warmed. Here is the profiler data for today from Seattle and you can see the strong SE flow off the Cascades.
And here is the model surface winds, pressure, and lower atmosphere temperatures at 2 PM. You can see the offshore flow there as well.
Here are the temperatures of the past 4 weeks...today really stands out as the first to really get above normal. In fact, this year is extremely late for us getting to the high-50s: the 5th coolest in that respect.