The best time to go to Ghana is during the northern hemisphere’s winter.
October through to April are not significantly hotter or cooler than other times of the year, but they are a great deal more comfortable as humidity levels are lower. These months form the dry season so there are fewer mosquitoes, game viewing is at its best as the grass is low, and resident bird populations are supplemented by all sorts of Palaearctic migrants.
The main disadvantage of the dry season, particularly from December through to February, is that visibility is seriously impeded by sands blown from the Sahara by the Harmattan winds.
If you would like to see the Akwasidae Festival in Kumasi, it is normally celebrated in July.