Butte sits at 5,500 feet (1,675 m) — winters are long and cold, summers short and warm. The best months are late June through early September, when the temperature settles into the high teens to mid-20s C and the surface attractions (the World Museum of Mining underground tour, the Our Lady of the Rockies bus, the drive-ins) are open.
The biggest event of the year is the St Patrick's Day parade on 17 March — Butte's Irish heritage is the deepest in the American West and the celebration spreads out over the whole week. The town is at capacity; book accommodation well ahead.
The summer Folk Festival in July, free and large, and the Evel Knievel Days in late July, are the other major dates. Winter brings serious snow but rarely closes the city.