Mountain gorillas can be seen any time of the year. We have never had visitors that have been to the jungles of Uganda or Rwanda and not see the mountain gorillas. The peak (busiest) time to track mountain gorillas is December to February and July to August. This is also arguably the best time to trek mountain gorillas in Uganda and Rwanda based on the favorable weather. These months are characterized as dry months with little on no rainfalls and the gorilla Parks are blooming with a big number of tourists. Scoring a gorilla trekking permit at this time of the year is difficult but it gets easier if you book early in advance and for assured scenarios its best you find a reputable tour company to do the booking for you.
The rainy months (April to May and September to November) are considered not an excellent time for mountain gorilla trekking. The brighter side is that these rainy months make one of the best gorilla trekking experiences as the gorillas usually hang around lower altitudes which makes it easier to track the gentle giants. There are also higher chances of getting better photos assuming it does not rain on our specific gorilla trekking day since during this time of the year the gorillas like to seek out the sun to sunbathe most of the day. The only downside behind trekking gorilla in the rainy months (April to May and September to November) is that the trek can be challenging due to the tracking being muddy but nevertheless with a pair of hiking boots, a waterproof jacket and a fair level of fitness, you are good to go.