The dry season in Botswana is from April to October, with the rains falling from November through to March.
In general, game viewing in Botswana is best between May and November. In April/early May, the grasses are still long and game viewing can be more challenging. From late May onwards, game viewing can be considered as excellent, though it is probably absolutely it is most dramatic at the end of the dry season from August to October. The landscape can look harsh during this time, but game viewing is easiest because grasses and foliage have withered or being eaten, and animals are reliant on more limited water sources. Migrant birds tend to start arriving in late September.
November usually brings the start of the rainy season, and whilst game viewing can still be excellent with great visibility, certain animals (particularly elephant and buffalo herds) will start to disperse as soon as enough rain has fallen for them to survive away from the permanent water sources.
The most challenging time of year to visit Botswana is from December to March, during the ‘green’ season, unless you are mainly interested in birds which are wonderful during this time. Having said this, in recent years we have found that neither weather systems or game viewing are totally consistent, and you definitely can enjoy some decent game viewing all year round. You just need a bit more more luck from December to March!
The exception to this rule is the Kalahari ecosystem, where game viewing is actually more productive during the rainy season (best from December to March) when game concentrates on the open plains and around pans. During the dry season, and particularly from July to October, the Kalahari is very harsh and game is widely dispersed.
The Okavango Delta floods annually between April (when the waters usually start to arrive) to June, so the best wetland ‘Okavango’ experience is usually had between May and September.
Temperature-wise, Botswana is temperate (not too hot or cold) in April and late August/ September. May through to late August is lovely and fresh, with clear sunny days but very, very cold evenings and early mornings. From late September onwards it can get very hot with day temperatures often exceeding 35°C and humidity increasing until the onset of the rains in November when temperatures drop off a little. December to March can be very hot and at times, humid.