If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Changsha County: The hottest months are usually August and July with an average temp of 81°F, while the coldest months are January and December with an average of 49°F. The rainiest months in Changsha County are June, May, July, and April, with each month seeing an average of 11 inches of rainfall.