The summer season runs from the Friday before Memorial Day, when the Beartooth Pass opens, to mid-October when the first snowstorm closes it. July and August are the busiest months — daytime highs around 80°F, cool nights at 7,000-feet elevation, the surrounding peaks usually with patches of snow into August. Restaurants on Broadway book out and lodging prices double.
September is the locals' favourite month: aspen turning gold on the highway, daytime temperatures still in the seventies, and the crowds thinning out after Labor Day. October is gambling weather — the pass can close on any night after the 1st.
Winter is ski season. December through March, Red Lodge Mountain runs daily and the town turns into a low-key alpine town with Christmas lights up on Broadway. January temperatures average a high of 35°F and a low around 12°F — bring layers. Spring (April–May) is the dead season; many restaurants close for two to four weeks, the pass is still under snow, and the snowmelt makes the trails miserable. Skip it.