Weather is probably a major factor when you plan your trip to Siran-dong, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually August and July with an average temp of 74°F, while the coldest months are January and February with an average of 41°F. The rainiest months in Siran-dong are July, August, September, and June, with each month seeing an average of 10 inches of rainfall.