The prospects of a La Niña weather system forming before the end of this calendar year have risen significantly over the past month, a state of affairs that points to wetter-than-usual weather over South Africa’s summer rainfall region, which includes much of the grain belt.
“The El Niño-Southern Oscillation (Enso) is still in a neutral state, however it has rapidly cooled in the last month,” the South African Weather Service said in its monthly Seasonal Climate Watch, which looks five months ahead — in this case to the end of February.
The Enso cooling refers to falling sea surface temperatures in the eastern Pacific Ocean, a development that gives rise to La Niña with implications for global weather patterns.
“There are still some predictions that maintain a neutral state. However, a La Niña state is more likely and gaining confidence as we near the summer seasons. The usual effect of La Niña on South Africa is for an increased likelihood to receive above-normal rainfall over the northeastern parts of the country during summer,” the weather service said.
Indeed, on Monday 29 September 2025 the US National Oceanic and Atmospheric Administration said that there was now a 71% chance of La Niña forming in the October to December period.
There are some qualifiers to the domestic outlook.
“There are indications that parts of Mpumalanga and Limpopo may receive below-normal rainfall during this period,” the weather service said.
And in keeping with recent forecasts the outlook remains for above-normal temperatures for most of South Africa this summer — which is also a reflection of global trends.
In a nutshell
After a blistering September across swathes of the country, things look set to really heat up while much of the summer rainfall region should get a drenching. That bodes well for dam levels and water security — at least where there is abundant rain — but is no panacea for the water woes caused by state failure and decayed infrastructure. But the hot weather will be a concern for dam levels and agriculture in areas that don’t get much rain, and that will be worrying when El Niño eventually returns.
The forecast bodes cautiously well for domestic agriculture and comes after South Africa’s maize harvest last season is estimated to have reached a robust 15.8 million tonnes, 23% above the previous summer’s crop that was hit by a scorching El Niño — La Niña’s polar opposite that typically brings drought to this region.
Another bumper harvest for the staple maize will, among other things, help to contain food inflation and provide relief to low-income households.
The weather service also warned of raised flooding risks in the months ahead, especially in areas with poor drainage systems.
At least there seems to be no signs of El Niño baring its fangs this summer. But in this global Enso weather dance, it will eventually take the stage again.
South Africa's 2025 summer rainfall season started unusually with rains in the western summer regions (e.g., Western Cape, Northern Cape), but forecasts suggest a shift to an eastern-focused pattern similar to 1987. In September 1987, Bloemfontein saw 170mm of rain (last such event until now), followed by a dry October-January and floods in February-April 1988, during a La Niña transition. For 2025, a weak La Niña (60% chance by October-December) may bring average-to-below-average rain in central-western areas (Free State, North West) in October-November, but above-average in eastern regions (KwaZulu-Natal, Mpumalanga) from December-March. This could echo 1987's eastern bias, with risks of dry spells early and wetter late summer, per SAWS and Agbiz forecasts. Farmers should prepare for variability amid La Niña's uncertain timing. La Niña, a climate pattern marked by cooler Pacific sea temperatures, typically brings above-average rainfall to southern Africa, contrasting with El Niño's droughts. For South Africa's 2025 agriculture—following a strong 2024-25 season with a record 19.94 million tonnes of summer grains and oilseeds (up 28% year-on-year)—La Niña offers both opportunities and risks. Forecasts indicate a 56-71% chance of weak La Niña conditions from September 2025 to February 2026, potentially weakening by March.
