Wayne's snow memory:

During the cross-country trip I took with Rob last year, we left Seattle, where it was in the mid-70s, on May 20. When we got the Yellowstone the next day, it was in the 20s and snowing like crazy. Neither of us had packed for winter weather, so we alternated freezing while looking at natural splendors with driving through the park giggling and saying, "It's May 21st...."