From November to April
From November to April
I loved the wildness of the Nxai Pan National Park. The highlight was Baine's Baobab, an island that's home to seven ancient baobabs.
The park surrounds a water hole, which is where this fossilised lake's water is at its deepest (it's a muddy basin). It remains a water source during the dry season and therefore attracts plenty of wildlife. It's why you'll catch sight of predators hunting National Geographic style - something which is less common in other well-known safari parks. It's also the season when migratory birds are in residence: pink flamingoes, storks...
For my part, I went during the dry season. Less interesting, perhaps, than the rainy season (fewer animals, arid landscape), but it meant that the roads were in better condition. This would, no doubt, explain why I found the scenery to be less impressive than the nearby Okavango Delta.
Even so, a great option is to spend one or two days in the public camp, from where you can admire the landscape surrounding the Okavango Delta road. You'll have some unexpected visitors (elephants, buffalo...), as the parks in Botswana are not fenced off.