Weather is probably a major factor when you plan your trip to Oyem, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually February and January with an average temp of 76°F, while the coldest months are July and August with an average of 73°F. The rainiest months in Oyem are October, September, May, and April, with each month seeing an average of 10 inches of rainfall.