Weather is probably a major factor when you plan your trip to Gaya-eup, but bear 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 temperature of 23°C, while the coldest months are January and December, with an average of 3°C. The rainiest months in Gaya-eup are July, August, September and June, with each month seeing an average of 218 mm of rainfall.