One factor that I am particularly fond of, is MAX temp. The highest recorded temp in the day. Average temp can be skewed by cold nights, when it's really the hot times in the day where the snow is degraded. Here is a graph of the MAX temp from the popular snotel sites across the west. (click to enlarge, hopefully)
I'd be really curious to know where your WA datapoint comes from. At a rough glance, I see most days with a high above freezing, and an average high around 5C (or 40F). As someone who skied this winter in WA, I'd call BS on that. I'm the first to admit that we go above freezing more than I'd like here, but those numbers seem flat out wrong to me.