Winters in Isehara are bitterly cold, with temperatures plummeting as low as -32°C in February and staying below freezing for most of the month. Spring brings a gradual warming trend, with April marking the beginning of mild days, reaching up to 26°C on occasion. Summer months are hot and humid, with July and August seeing temperatures soar above 35°C, while autumn is characterized by cooler days, descending back into chilly nights as winter approaches once more. November's temperature fluctuations reflect this transition, with warm days giving way to frosty mornings.