mid december to mid march all Yellowstone park roads are closed
to cars; except the road between Gardiner and Cooke City in the
West-Yellowstone, MT is the most important winter gateway to the
park. From here You can enter by snow coach or snow mobile. Snow
mobiles offer the greatest flexibility for exploration. Be prepared
for a chilly experience. Temperatures can easily drop to -20F
in the morning. Riding at 35mph on a snow machine will add a lot
of extra windchill.