If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Chengdu: The hottest months are usually August and July with an average temp of 78°F, while the coldest months are January and February with an average of 50°F. The rainiest months in Chengdu are July, August, September, and June, with each month seeing an average of 9 inches of rainfall.