When someone thinks of Africa, they often think of expansive deserts or large savannahs with sweltering heat. This isn't actually the case in Johannesburg, in sub-Saharan Africa.
Johannesburg is in what is considered the South African highlands, or Highveld. Johannesburg's elevation is at 1,753 meters and this helps keep the temperatures cool during the summer months. The Gauteng region is said to have one of the most pleasing climates in South Africa. Average temperatures throughout the year are quite enjoyable. The climate is very similar to Lisbon, Portugal, except Johannesburg's clearer skies will mean more sunshine.
The most distinct seasons in Johannesburg are summer and winter, with short periods of spring and autumn buffering the summers and winters. Summers are often considered to be the rainy season and lasts from November to February. Winters are very dry during the months from May to August.
The best time to visit Johannesburg is during the short autumn & fall seasons between summers and winters. The crowds begin to thin out, the days aren't too hot, and the nights aren't too cold. Prices for hotels and flights are also typically lower. Short periods of rain may be a welcome change to dry days, but it's nothing like the popular, rainy summer months.
Summer Weather in Johannesburg
The hottest month in Johannesburg is January, right in the middle of Johannesburg's summer. The high elevation often keeps the average daytime high to 26°C though the hottest day on record reached 41°C. This usually only occurs in the lower elevations surrounding Johannesburg. Temperature variations between the beginning and end of summer are quite insignificant, averaging 25°C in November and 24°C in March.
January is also the wettest month in Johannesburg. Rainfall totals in Johannesburg usually don't exceed 120mm per month in the summer and are spread out over an average of 15 days. The rains that do come usually occur in brief, powerful downpours during the afternoons. Lightning, thunder, and hail can be intense at times. Periods of steady drizzle are extremely rare. These numbers are typical for all summer months.
These late afternoon downpours, and the city's high elevation, contribute to cool nights. The average lows for summer are usually around 14°C and happen during the short change in seasons. The lowest temperature ever recorded during summer occurred in November, with a chilly 1.5°C. Humidity levels rarely rise above 70%.
Summer is a great time to be active outdoors in Johannesburg. Because the daytime temperatures don't get too hot and humidity levels are very comfortable, summers are a great time to go on safaris or rafting trips in the Magaliesburg mountains. Anticipate evening showers, but otherwise you'll be presented with moderate temperatures and sunny skies. The days are long and average 10-11 hours of sunshine throughout summer months.
Extreme Weather
An intense hailstorm in December of 2017 caused significant damage, destroying cars and causing roofs to collapse throughout the city.
Johannesburg has been seeing more and more of these storms in recent years. Rising temperatures have been producing severe afternoon thunderstorms, causing terrible flash flooding. Record flooding swept through Johannesburg in 2015 and 2016. Other hail events have also been recorded and are expected to get worse.
The best way to know if such conditions may exist during your visit is to check the forecast before your visit.
Autumn Weather in Johannesburg
Autumn is a very short transitory period for Johannesburg, occurring in the six weeks around April. The weather is characterized by cooler temperatures and a decrease in rain.
The average daytime high is 22°C and nights fall to 10°C. The record high in April was 30°C and the record low 0°C.
Sunshine is still abundant in autumn and you'll see nine hours of it, shortened only by the decreasing length of days. Tapering rains usually only deliver 40mm of rain spread out over 8 days, again in the form of short, passing afternoon storms.
Autumn is a splendid time to visit Johannesburg's parks. The bright blue skies will contrast against the golden & deep red leaves, a photographer's dream. Yet, the temperatures are still perfect for all of the same outdoor activities such as safaris, hiking, and mountain biking.
Winter Weather in Johannesburg
Crisp, blue skies and cooler night signal the arrival of winter in Johannesburg. During May, the beginning of winter, daytime highs will be 20°C and nights fall to 8°C. By mid-June, the coldest month in Johannesburg, the daytime temperatures fall to 16°C and the nights at 4°C. The record low for a winter in Johannesburg was recorded at -8°C, occurring in June. The hottest temperature ever recorded in winter was 26°C, occurring in both of the shoulder months of May and August. Winter in Johannesburg is very similar to winter in Barcelona but with just a touch less rain.
It's very rare to see any rain during winter in Johannesburg. It may sprinkle for a day or two, but average rainfall totals every month throughout summer rarely exceed 10mm of rain, occurring for usually no more than 2 days a month.
The dry air and temperatures just above freezing means that it hardly ever snows in Johannesburg. There have been seven instances of snow in seventy years, the last occurring in 2012 when only a trace of snow was recorded.
Because the days still reach 15°C, outdoor activities are still fun. You will have to dress warmer if you'll be out after dark, but activities like safaris, tours, and hiking are still enjoyable. You'll still have 9-10 hours of sunshine and humidity levels hover right around 50%.
Spring Weather in Johannesburg
Johannesburg is quite beautiful in spring. The many parks and gardens in all of the city's green areas start to bloom and the tourist season comes to an end.
Temperatures start to slowly warm up. September's highs and lows are 22°C and 9°C, while October's temperature range is 24°C and 11°C. The record high in October is 32°C and the record low from September is a chilly -3.3°C.
The transition into summer means that spring will see some rains. The probability of precipitation in early September is only 5% while the by the end of October it climbs to 36%. Rainfall totals are between 40mm-80mm, so, still dry.
Days start to get longer and you'll get 11 hours of sunshine during spring. Thanks to the abundant sunshine, warming temperatures, and small chances of rain, spring also gives you excellent conditions to explore Johannesburg and the surrounding areas. You'll also have the added bonus of visiting during the off-season for tourism.