Amakusa's winters are mild, with temperatures rarely dropping below freezing and averaging around 7-9°C in January and February. Spring brings a steady warming trend, with temperatures rising to an average of 16-19°C by April and May. Summer is hot and humid, with July being the warmest month, but August is also very warm. Autumn sees a gradual cooling down, with temperatures dipping back into single digits by November, mirroring the winter pattern.