Weather is probably a major factor when you plan your trip to Keylong, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually June and May with an average temp of 84°F, while the coldest months are January and December with an average of 58°F. The rainiest months in Keylong are July, August, September, and February, with each month seeing an average of 8 inches of rainfall.