How much snow does Yellowstone get? If you look at the red pole in the lower right hand corner of the picture, you'll get an idea. The pole, which is used to guide snow plows, indicates that there can be a LOT of snow there.
Why? Part of the reason is the altitude. Much of Yellowstone is at 8,000 feet above sea level. That's why it's frequently the coldest spot in Wyoming. And because of that, the park has recorded snow in every month of the year. Yes, even July and August.