Weather will likely play an important role when you plan your trip to Heshan, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually August and July, with an average temperature of 28°C, while the coldest months are January and December, with an average of 15°C. The rainiest months in Heshan are June, May, July and August, with each month seeing an average of 287 mm of rainfall.