October in Siheung is the sunniest month of the year. In October, the weather in Siheung is typically warm. Average daily high temperature in October is about 18 degrees above zero. On average, Siheung has 22 sunny, 8 partly cloudy, and 1 rainy day in October. The rains are usually moderate. October as well as May and September is considered the most comfortable time to visit Siheung.