average annual rainfall johannesburg
Rainfall/ Precipitation in Johannesburg, South Africa. 1  Johannesburg is handed on average 543 mm (21.4 in) of rainfall per year, or 45.3 mm (1.8 in) per month. 2  On average there are 96 days per year with more than 0.1 mm (0.004 in) of rainfall (precipitation) or 8 days with a quantity of rain, sleet, snow etc. per month.