Cumulonimbus Clouds Building up over African Savannah During Rainy Season - Inter Tropical Convergence Zone.

In Zambia, which is 14 degrees south of the equator, the rainy season normally starts in November each year as the sun moves south of the equator, bringing with it the inter tropical convergence zone (ITCZ).

This creates massive cumulonimbus clouds that produce torrential rain and spectacular thunderstorms. It is known locally as the Rainy Season and in India and SE Asia, it is called the monsoon. In some reports the term monsoon is also applied to the Southern Africa rainy season.

This rain is needed to refill the rivers and the hydro electric reservoirs, the latter providing cheap electricity that is not subject to foreign exchange fluctuations, as imported fossil fuels are.

The rains also provide water for wildlife and for the towns and cities and is used by rural communities and farmers to grow seasonal crops.

Another term for the ITCZ, used historically in seafaring circles, is the ‘doldrums’ since the winds along the band of low pressure are typically calm, trapping sailing ships for days or even weeks at a time leaving them stranded.