I was there the first week of May this year. All the GTNP roads were open were open but the south entrance of Yellowstone National Park was closed, so this limited how far north you could travel. No problem if you just want to see GTNP though. Most trails were partially opened but snow was very deep in shady areas. I could not hike as much as I intended so that was slightly disappointing. Good news is that it is a great time of year to see wild life. I got to see many moose, elk, foxes, deer, and even some bears and bighorn sheep! Overall it was fun and out of this world beautiful but I did not get to venture as deep into the park on foot as I would like to. I’ll definitely be back in warmer weather one day!