The world's first national park — a volcanic hotspot of geysers, hot springs, and the largest supervolcano in North America.
Late April–May and September–October for wildlife and fewer people; July–August has the warmest weather and the widest road access.
July is busiest, and parking waits at Old Faithful, Grand Prismatic and Canyon can be long — visit early or late. Winter offers snowcoach tours and wolf watching with very few people.
Most park roads close to cars from early November to mid-April (the road from the north entrance to Cooke City stays open). Snow can fall in any month at elevation, and summer brings thunderstorms and cold nights.
General patterns — conditions vary by year. Check current NPS alerts and road status before you go.
Distances are rough estimates to the closest entrance. Check road and ferry conditions before you go.
Campgrounds inside the park are booked through Recreation.gov, and many fill months ahead.
FIND CAMPSITES ON RECREATION.GOV ↗