Rwanda can be visit anytime of the year. There is not such weather that would stop you from visiting or more specifically mountain gorilla trekking. However most people prefer to take safaris during the drier months of the year. This is because wildlife viewing trails are not boggy and easily accessed.
June to Mid-September and December to February
This time of the year is usually dry and the best time to visit Rwanda. For those who want to trek and do canopy walks this is the best time because the trails are dry and passable. However most of them are is a tropical rain forest especially PNV and so you definitely have to carry a jacket and boots just in case, nature here is unpredictable.
Hiking is also easier during this season. Game viewing becomes also easier as most animals will converge at water sources since it’s a dry period therefore you have chances of seeing all of them in just one place. And it makes it quite obvious of where you are going to find the animals during this season.
March to May and October to November.
These months are the rainy months in Rwanda. But it does not mean that it will rain throughout the entire season if you have may be a 5 day safari, you may not even encounter any rain in this season. Unlike the west in Africa and particularly Rwanda, it may rain for a few hours and then shine for the rest of the day. This therefore means that the activities you plan may still be achievable.
However for those looking at birding, this could be one of the best times to come to Rwanda depending on the bird species you are looking at. At this time most of the plants are flowering and therefore attracting birds.
Photographers can also visit during this time as the entire area is green and all plants are flourishing. Since most people prefer travelling June to September you are advised to travel either may or October as you will not miss much and will have reduced costs but if you choose to travel during that period please book early enough and most attractions in Rwanda have a daily limit number of visitors.