The best time of year to visit Tanzania – if you’re after large quantities of animals that is, is between June and October. This is the dry season across most of the country. While this is particularly the case in Ruaha and Selous in Southern Tanzania, Katavi in Western Tanzania and the Mahale Mountains on Lake Tanganyika, it’s by no means the case for all parks. Between December and May for example throws up some of the best game viewing available in all Africa in the Serengeti and surrounding areas.
The Ngorongoro Highlands can still be full of flowers in June and July, but be prepared for cold with low cloud hanging often around till midday. Tarangire in Northern Tanzania, which acts as a dry season refuge for wildlife from the entire Maasai Steppe is at its best for game between late July to late October. However it’s always good for elephant and in the green season between December and May it has tremendous birdlife.
The Serengeti offers spectacular game viewing year round, so works a bit differently. What matters here is that you head to the right part of the park for the time of year and that you avoid the main tourist traps.
If the wildebeest migration is a major objective, then there isn’t really a “best” time to visit. River crossings happen between July and October on either the Grumeti or the Mara River, and the calving, one of the most spectacular times to visit, happens in February.
Game action remains excellent through the unfashionable months of March, April and May when the wildebeest start moving off the plains during the rut. Low visitor numbers make this a great time to visit.
If you’re traveling between December and May, then it’s worth combining Southern Plains with Loliondo, if you’re interested in walking, nightdriving and more of a wilderness experience.
People tend to overlook the green season months in Southern and Western Tanzania, but between December and the end of February can be a great time to visit. Selous becomes humid which makes it less good for long walking safaris but the river is high, everything is green and young animals and migrant bird species are plentiful.
In Ruaha the bush can have closed in a bit making wildlife viewing less easy in some areas, but game remains plentiful, so long as you’re not in a hurry.
The water levels will have started rising in Katavi and you may not encounter such large concentrations of animals, but as long as you don’t rush things, this is a much more benign season to be there and there is plenty to see.