Planning for the weather is a good way to make your trip to Daejeon relaxing and enjoyable, especially when you're splurging. 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 1°C. The rainiest months in Daejeon are July, August, September and June, with each month seeing an average of 205 mm of rainfall.