Busan's spring is mild, with temperatures gradually warming up from March's average of 18°C, reaching a peak in May at an average of 25°C. Summer brings sweltering heat, especially in August when the mercury soars to an average high of 34°C, but cools down slightly by July and September. Autumn is marked by significant temperature fluctuations, with October averaging 17°C, while November and December usher in a chilly winter, with temperatures plummeting to as low as -9°C in December.