Most visitors come in January for the Ice and Snow Festival, which typically runs from early January through February. This is when the city is at its most spectacular — and its most cold. Temperatures routinely drop to -25°C or below, and wind chill can push the feel significantly colder. Pack extreme cold-weather gear: thermal base layers, down parka, waterproof outer shell, wool socks, and insulated waterproof boots. Mittens beat gloves.
Summer (June to August) is warm and green, and the city takes on a completely different character. The riverside parks fill up, boats run on the Songhua, and the Russian architecture is easier to appreciate without hat-and-scarf tunnel vision. Autumn (September-October) is brief but pleasant. Spring can be muddy. Winter, despite the cold, is the reason Harbin is on the map — come properly dressed and it is extraordinary.