If you're hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Guigang: 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 16°C. The rainiest months in Guigang are June, May, August and July, with each month seeing an average of 260 mm of rainfall.