Helena has a classic continental mountain climate: cold, snowy winters and warm, relatively dry summers. July and August are the most popular months and bring genuine warmth (highs around 30°C), though afternoon thunderstorms are common. May and September are the best shoulder months — the trails on Mount Helena are clear of snow, the air is cool, and the city is quiet. Winter is cold (lows regularly below -15°C) and Helena gets significant snow, though the skiing at Great Divide, about 30 kilometers north, makes that worthwhile for some visitors.