Planning for the weather is a good way to make your trip to Uljin relaxing and enjoyable, especially when you're splurging. The hottest months are usually August and July with an average temp of 72°F, while the coldest months are January and February with an average of 39°F. The rainiest months in Uljin are August, July, September, and October, with each month seeing an average of 8 inches of rainfall.