Joetsu's winters are harsh, with temperatures often plummeting below freezing, averaging just 1°C in January. Spring brings a gradual warming trend, with April typically being the warmest month of the season, averaging 11°C. Summer is hot and humid, with July and August frequently seeing highs above 35°C. Autumn is mild, with October experiencing warm days and cool nights, averaging 16°C. Winters are cold again, with December temperatures sometimes dipping below -8°C.