Johannesburg, South Africa's largest city, sits inland on the high interior plateau known as the Highveld, at around 1,750 metres above sea level in the northeast of the country, at approximately 26.20°S, 28.05°E. Its considerable altitude tempers its subtropical latitude, giving it a mild, sunny subtropical highland climate (Köppen Cwb) with warm, rainy summers and dry, sunny winters with cold nights. Being in the Southern Hemisphere, its seasons are reversed relative to the Northern.

Summer, from October to March, is warm rather than hot, with the warmest months around 26°C by day — kept comfortable by the high elevation — and mild nights. It is the rainy season, famous for its dramatic late-afternoon thunderstorms: humid air from the Indian Ocean builds through the day into spectacular storms with lightning, heavy downpours and sometimes hail, which clear quickly to leave a fresh, earthy-smelling evening. Mornings are typically bright and sunny before the storms build.

Winter, from June to August, is dry, sunny and mild by day but cold at night, with June and July the coolest — average highs around 16–17°C but nights that regularly fall close to freezing, with frost common and occasional dips below zero. Rain is essentially absent, skies are clear and blue, and the crisp, sunny winter days give way to cold, still nights. Snow is a rare event, last falling in any quantity in 2012.

Johannesburg receives around 710–760 mm of rain a year, overwhelmingly concentrated in the summer months from November to March, when roughly 90–120 mm can fall per month as afternoon thunderstorms; the winter from May to August is very dry. Live rainfall, humidity, and pressure readings for the city are shown in the panels above.

Johannesburg's altitude is the key to its pleasant climate, giving it mild summers and crisp, sunny winters quite unlike the subtropical heat its latitude might suggest, along with cold, frosty winter nights. The city's signature weather is the Highveld thunderstorm — the spectacular electrical storms that roll across the plateau on summer afternoons — while its high, clear air gives it abundant sunshine and famously luminous skies throughout the year.

To follow any single measurement in Johannesburg more closely, use our live instruments: the online barometer for atmospheric pressure, the thermometer for temperature, the hygrometer for humidity, the anemometer for wind speed, the wind vane for wind direction, and the rain gauge for rainfall.