Nikko's winters are chilly and unpredictable, with temperatures often dropping below freezing in January and December, but occasionally rising above 18°C. Spring arrives in March, bringing mild temperatures that gradually warm up into April and May, with daytime highs frequently reaching the mid-20s to low 30s Celsius. Summer is hot and humid, with July and August being the warmest months, while September brings a welcome cooling trend as the mercury drops back down. Autumn sees a return to more moderate temperatures in October and November, before winter sets in once again.