Tanzania has two rainy seasons from; October to December- short rains and from March to the end of May- long rains. It also has two dry seasons; a long dry season from June to October and the short one of January and February. These dry seasons are the best periods to visit Tanzania though parks like Serengeti and Ngorongoro can still be visited even in the wet seasons. The long dry season is perfect for Serengeti because of the popular Wildebeest Great Migration.