Why are there so many black people in South Africa when the temperature is not high?

The reason why there are so many black people in South Africa despite the low temperature is that the Bantu people (black people) in the Congo River Basin migrated south in large numbers.

Except for the northernmost part of South Africa, the climate in most areas is very mild, with warm winters and cool summers, and the climate is pleasant. People with lighter skin live here.

In fact, the San and Khoi indigenous people here have relatively light skin color, which is in line with the ecological characteristics here.

But later, the Bantu people (blacks) in the Congo River Basin moved south in large numbers, and there were more and more blacks in South Africa.