Great all year round, especially June until October, but watch out for the main rainy season in April and May.
Kenya has a great climate for most of the year. In terms of weather the best time to visit is between June and October. The weather is hot, but not humid, and the game viewing is excellent. Kenya is also a great winter sun option, however it can be very humid between October and May. The major rainy season to avoid is in April and May when all of the camps are closed. There is also a shorter rainy season that tends to fall at some point in November and December. However, most camps remain open during these months.