There’s nothing like an all-inclusive vacation in Ruaha National Park to rejuvenate you, especially when you know what kind of weather to expect. Here’s some info to help you decide when to book: The hottest months are usually October and November with an average temp of 68°F, while the coldest months are July and June with an average of 63°F. July and August are the driest months while January and March are the rainiest months.