Dependant on your travel period, weather conditions may vary. There is no rule of thumb but generally speaking, this is how the weather behaves in Botswana
November to March – these are the summer months and rainy season. Days and nights are hot with temperatures reaching +-30 degrees. As it is also the rainy season, showers are to be expected.
April and May – it is usually the end of the rainy season; however an odd rain shower or storm might appear here and there experience the odd rain shower. The temperatures are still high during the day, though cooler than over the summer months, but towards night and early morning it starts to get cooler
June to early September – are the winter months here in Botswana. Believe or not early mornings and evenings can get very cold, with temperatures dropping below 10 degrees Celsius. In more deserts like regions such as the Kalahari it gets even colder. On the other hand, the temperature during the day is very pleasant ranging between 23-26 degrees.
Mid-September and October – September is the end of the winter, where evenings and early mornings could still be bit chilly but the days are rapidly warming up. October is the hottest month of the year day and night temperatures easily oscillate between 30 – 40 degrees.