South Sudan's protected area of Bandingilo National Park hosts the second-largest wildlife migration in the world. Surveys have revealed that Boma National Park, west of the Ethiopian border, as well as the Sudd wetland and Southern National Park near the border with Congo, provided habitat for large populations of hartebeest, kob, topi, buffalo, elephants, giraffes, and lions.
South Sudan's forest reserves also provided habitat for bongo, giant forest hogs, red river hogs, forest elephants, chimpanzees, and forest monkeys. Surveys begun in 2005 by WCS in partnership with the semi-autonomous government of Southern Sudan revealed that significant, though diminished wildlife populations still exist, and that, astonishingly, the huge migration of 1.3 million antelopes in the southeast is substantially intact.
South Sudan map of Köppen climate classification.
South Sudan has a climate similar to an Equatorial or tropical climate, characterized by a rainy season of high humidity and large amounts of rainfall followed by a drier season. The temperature on average is always high with July being the coolest month with an average temperatures falling between 20 and 30 °C (68 and 86 °F) and March being the warmest month with average temperatures ranging from 23 to 37 °C (73 to 98 °F).
The most rainfall is seen between May and October, but the rainy season can commence in April and extend until November. On average May is the wettest month. The season is "influenced by the annual shift of the Inter-Tropical Zone" and the shift to southerly and southwesterly winds leading to slightly lower temperatures, higher humidity, and more cloud coverage.
Source : Wikipedia