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 temp of 72°F, while the coldest months are January and December with an average of 60°F. The rainiest months in Ruili are July, August, June, and September, with each month seeing an average of 19 inches of rainfall.