Why does the Zambezi River flow much less in October and November?

The Zambezi River experiences significantly lower flow in October and November because these months fall at the end of the region's dry season, just before the onset of the primary rainy season.12

The river's discharge is highly dependent on seasonal rainfall, which occurs primarily between November and April. During the months leading up to November, the region experiences high temperatures and minimal precipitation, leading to a substantial reduction in water volume. By October and November, the river's flow typically diminishes to less than 10 percent of the maximum levels recorded during the peak of the rainy season in March or April.12