Rwanda has two dry seasons: June to September and December to February. The long dry season from June to September is the best time to visit. Roads into Nyungwe are passable and the forest trails are easier to navigate in dry conditions. Wildlife viewing in Rusizi National Park is good year-round, but hippos and crocodiles are most visible when water levels are lower in the dry months.
The long rainy season runs from March to May — the roads into Nyungwe can become difficult, and the forest is extremely wet. The short rains from October to November are lighter and less disruptive. Chimpanzee tracking permits are available throughout the year but booking well ahead is essential in the peak June–September season.
Cyangugu is at around 1,500 metres elevation, which tempers the heat — days are warm and comfortable rather than hot, and nights are cool.