Fourth of July at Mammoth — no snow, but the mountain bike trails are open. Rated ★★★★☆
Adding a summertime review. We were here on the fourth of July, no snow but the mountain bike trails were open and awesome! You have to get a lift/area pass, and we rented bikes (and helmets and pads) from the Canyon Lodge, expensive but worth it.
There’s a bus/bike trailer that takes you up to the “Mammoth Adventure Center” — from there you can take lifts up higher on the hill or just ride back to Canyon Lodge, which we did, twice, since we only had a couple of hours. It’s not all downhill, and the uphills were at about 8000’ on a hot day so we definitely got a workout. Downhill was fun and beats up your body even if you don’t throw yourself over the handlebars! Trails are well-built and not too busy even on a holiday weekend.