Qiqihar's visit timing is largely dictated by the cranes at Zhalong, since that is why most non-Chinese visitors make the trip.
Spring (April–May) is the prime crane breeding season. Red-crowned cranes arrive from their wintering grounds in Korea and Japan in March and April, and by May the breeding activity is well underway. The reserve is at its most dynamic, and the weather — cool and often clear — makes birding comfortable.
Early autumn (September–October) is the other strong window. Cranes gather before their autumn migration, numbers are high, and the flat grassland and marsh of the reserve turns golden. This is also when the city itself is most pleasant — warm but not hot, dry, and with a clarity in the light that summer's humidity lacks.
Summer (June–August) is hot and sometimes very humid, with temperatures reaching 35°C. The cranes are present but the conditions are less comfortable. The night markets around the city are at their best in summer, which is some compensation.
Winter in Qiqihar is harsh — temperatures reach -30°C or lower — and the reserve is largely frozen and birdless. There is little reason to visit unless you are passing through on the way to somewhere colder.