A woman crosses a street during a severe storm in Johannesburg. According to the SA Weather Service, Joburg's summer will be wet, humid and cloudy. (Photo: Gallo Images / Netwerk24 / Felix Dlangamandla) 
Over the past couple of weeks, the weather in Johannesburg has been a little like that old Med-Lemon advert — sometimes it’s hot, sometimes it’s cold — leaving many residents asking: “What on earth is happening with Johannesburg’s weather?”
Many residents have woken up to wet, cloudy skies one day, only to find clear skies and scorching heat the next. South African Weather Service (Saws) meteorologist Lehlohonolo Thobela filled Daily Maverick in on what exactly is going on.
Read more: Has Joburg skipped spring? Scientists explain why it feels like winter turned straight into summer
Warm, wet summer loading
“South Africa’s 2025/26 summer is shaping up to be a wet, humid and cloudy one, especially across the eastern regions. As a weak La Niña begins to take hold, expect above-normal rainfall, warmer nights and milder daytime highs due to persistent cloud cover, as the seasonal forecast suggests below maximum temperatures for the season,” Thobela said.
La Niña is a natural climate pattern categorised by the cooling of sea-surface temperatures in the equatorial Pacific Ocean. This phase of the El Niño-Southern Oscillation (Enso) cycle is often associated with increased rainfall in the eastern and central regions of South Africa.
Read more: It’s back! La Niña has formed, raising rain hopes for SA farmers this summer
Thobela explained that while these wetter conditions may benefit agriculture and water resources, they may also raise flood risks in low-lying or flood-prone areas.
The eastern part of South Africa will also be cloudier, due to tropical moisture inflow from the Indian Ocean, frequent convective activity triggered by the moist, unstable atmosphere, and a persistent upper-air circulation pattern that supports widespread rainfall and reduces surface heating.
In terms of heat, Saws’ climate watch projects that minimum temperatures are expected to be above normal across much of the country, while in the eastern and north-eastern regions (which include Gauteng) temperatures are not likely to exceed maximum projections.
The cooler daytime highs are mainly due to prolonged cloud cover and increased humidity, both typical of a La Niña-dominated summer.
So what should residents expect as Joburg moves towards summer?
“Considering that the seasonal forecast suggests above-normal rainfall in the central and eastern regions, with more cloud cover and below-normal temperatures, the likelihood is high that these regions will experience more cool, wet conditions,” Thobela said.
So before you leave the house, be sure to carry your umbrella and raincoat, just in case. DM