Shiretoko has dramatically different characters in different seasons, and what you want to see should determine when you come. Summer (June–August) offers the fullest access — all roads open, whale watching, bear watching along the coast, and Shiretoko Goko's ground trail accessible. July and August are the warmest months but also the most crowded.
Winter (late January to March) is remarkable for the drift ice and the huge concentrations of sea eagles it brings. The Shiretoko Pass road closes and access is limited to the Utoro side, but ice-breaking cruises and the wildlife they support are worth the journey. Early spring (April–May) brings dramatic snowmelt, migratory birds, and bears emerging from hibernation; the pass road reopens around late April or May. Autumn (September–October) is beautiful — bears are fat and highly visible before hibernation, foliage colours are excellent, and the crowds have thinned.