If you're looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Wanju: The hottest months are usually August and July, with an average temperature of 23°C, while the coldest months are January and February, with an average of 2°C. The rainiest months in Wanju are July, August, September and June, with each month seeing an average of 200 mm of rainfall.