Elevation changes and even more dramatically in the Northwest. You can start from sea level and get to 3000 often times within 1 hour of driving. Looking at the pacific coastal range, glaciers and snow are often times a short distance away from the beach even in the middle of summer. If you look at low land close to sea level, temporature is usually between 30's to 40's F in winter. Drive 1 hour and you'll be at 20's. All the more reason to prepare for winter driving conditions....