Hannan, Japan experiences a temperate climate with distinct seasonal variations. Winters are cool and somewhat unpredictable, with temperatures ranging from -6°C to 18°C in January, and -3°C to 20°C in February. As spring arrives, temperatures rise gradually, reaching an average of 15°C in April, followed by a warm summer with highs often above 30°C from May to August. Autumn brings milder conditions, with September being the warmest month on average, before cooling down again in November and December, which are relatively chilly, with temperatures fluctuating between -2°C and 19°C.