Re: weahter Washington, Oregom Marcha April
Yes, both are "shoulder months" marking a transition from very frequent rain and very chilly temps to more showery weather and warmer temps.
All the high country in the Cascades, Olympics, and higher parts of the coastal range will be snowed in except for the major plowed routes. Many of the roads in the Cascades don't open until May, June, or even July. The plowed roads will be passable most of the time, but you can get near-blizzard-like conditions even in the low passes in April.
The high-deserts of E. WA and E. Oregon can be fairly pleasant in April and may have spurts of pretty nice weather in March. Some of this area is very dry and generally sunny almost year round. But elevations will be cold and icy. Most of the high country in NE Oregon doesn't open up until May. One of the coldest places in the lower-48 is Ukiah Oregon, right in the heart of some of the best riding in the country. But they commonly record well-below-zero temps in March. Roads will be VERY sandy from the winter's traction sanding.
The lowlands in Puget sound and down the coast will be often wet and coolish (highs in mid-50's), but there will be spurts of sunny 60-deg weather, especially in April.
WA and OR are huge states. Where are you planning on riding? This is a time of the year where you need a lot of schedule and route flexibility. And it really is way too early to be thinking about playing in the mountains - you have to stay out of elevation.
- Mark