We're going to Yellowstone and the Grand Tetons National Parks for 3 days each. Probably won't have much time to do any hiking at Yellowstone since it's such a big park and we have so little time to see everything.
We'll have more time to do backcountry hiking in the Tetons. With the overnight lows in the 40's and daytime highs of 70, we couldn't ask for a better temperature profile for our trip.