Taking into account the local weather in Johannesburg is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually July and August with an average temp of 64°F, while the coldest months are February and January with an average of 23°F. The snowiest months in Johannesburg are January, November, February, and March, with each month seeing an average of 17 inches of snowfall.