Mohe has two distinct visitor seasons separated by a short, muddy shoulder. Pick one deliberately — the city rewards commitment to either extreme.
Winter (November–March) is aurora season. Temperatures drop reliably to -30°C or -40°C, which sounds punishing but is dry and still, making it tolerable with the right clothing. December through February gives the longest dark nights and the best aurora odds. The Ice and Snow Festival peaks in January and February. Pack more warm layers than you think you need; the cold here is not a minor inconvenience.
Summer (June–August) brings the midnight sun phenomenon. Around the solstice in late June, the sun sets briefly around 11pm and rises again before 3am, leaving the sky never fully dark. The long golden light on the river and forest is beautiful, temperatures are warm (occasionally hot), and the mosquitoes are aggressive. This is hiking and river season.
Spring and autumn are brief, grey, and of limited appeal. The ice breakup in April is dramatic but visiting for it alone requires real commitment. September brings the first frosts and the first colour in the birch forest.