If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Changwon: The hottest months are usually August and July, with an average temperature of 24°C, while the coldest months are January and December, with an average of 5°C. The rainiest months in Changwon are July, August, September and June, with each month seeing an average of 214 mm of rainfall.