Weather is probably a major factor when you plan your trip to Zhongshan, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually July and August, with an average temperature of 29°C, while the coldest months are January and December, with an average of 18°C. The rainiest months in Zhongshan are June, August, May and September, with each month seeing an average of 320 mm of rainfall.