THE CLIMATE IN GENERAL 303 



Angola. The low rainfall of the southern coastal 

 lands is due to the effect of cold ocean currents, 

 which, by keeping the sea breezes cool and dry, 

 prevent rainfall from the sea ; whilst the coastal 

 mountain chain prevents any moisture-laden clouds 

 from the south-east and east passing on their rain 

 to tiie coast. 



It is only on the northern coast, where the 

 current has lost its low temperature by mixing 

 with warm ocean waters, or when the ocean 

 wind has been warmed by contact with the western 

 walls of the highlands, that the now warmed sea 

 breezes can hold suiiicient moisture to bring rain. 

 For this reason the north coast-lands and the 

 western slopes of the highlands have a compara- 

 tively heavy rainfall. 



The rainfall which occurs from September to 

 March is accompanied in Angola, as almost every- 

 where else in Africa, by much thunder and 

 lightning, and is short in duration, with heavy 

 showera. In my experience of the wet season, 

 the rain usually came in the afternoon, the morn- 

 ings being fine ; the prevailing rain-bringing wind 

 behif>- from the east rather than the west, due 

 partly to the fact that strong, moisture -laden 

 winds from East Africa appear to reach even to 

 Angola. 



Important factors in the climate of Angola, 

 to its disadvantage, are the extreme contrast 

 between vhe dry and wet season, and variation 

 of temperature between day and night ; a day 

 temperature, which would suit a tropical plant 

 or permit Lhc scantiest clothing on a human body, 



