Highway 20 is closed during the winter due to avalanche danger. And yes, shorts weather is about that degree range over here. The west side of the cascades, I'd say probably 50° on the low end just because of the humidity. The east side is dryer, so shorts weather is more of what you're accustomed to over here. The entire state is incredibly geologically diverse, from the rain forests on the peninsula, to the San Juan Islands and puget sound, the cascades range, to the channeled scablands in the central part of the state, awesome forests in the NE corner, down to the walla walla Valley, blue mountains, and clarkston in the SE corner, which is the gateway to hells canyon. There is a LOT to check out here! :)