 Guangnan, as with much of southern Yunnan, has a warm humid subtropical climate (Köppen "Cwa"), with muddled distinction between the seasons and daytime temperatures remaining warm year-round.The warmest and coolest months are July and January, respectively at and ; the annual mean is .May thru September accounts for nearly 75% of the annual rainfall of 

The following information in this section is from the "Guangnan County Almanac" () (2001).