Planning for the weather is an important factor for making your trip to Jeju City a success, especially when you’re splurging. The hottest months are usually August and July, with an average temperature of 24°C, while the coldest months are January and February, with an average of 8°C. The rainiest months in Jeju City are July, September, August and June, with each month seeing an average of 279 mm of rainfall.