You'll likely spend much of your trip indoors, but if you're planning to venture beyond the casino, looking at local weather trends is a good idea. The hottest months are usually April and May, with an average temperature of 22°C, while the coldest months are January and December, with an average of 16°C. The rainiest months in Ruili are July, August, June and September, with each month seeing an average of 492 mm of rainfall.