La Niña has finally formed, but will be over soon, says US National Weather Service

The La Niña weather pattern – which usually brings good rains to much of southern Africa – finally emerged in December, the US National Weather Service said late last week.

But as widely forecast, it is weak and will not hang around for long. Blink and you might just miss it.

“La Niña conditions emerged in December 2024 and were reflected in below-average sea surface temperatures (SSTs) across the central and east-central equatorial Pacific Ocean,” the service’s Climate Prediction Centre (CPC) said.

“La Niña conditions are present and are expected to persist through February-April 2025 (59% chance), with a transition to ENSO-neutral likely during March-May 2025 (60% chance),” it said.

ENSO is the El Niño-Southern Oscillation and neutral is the phase between La Niña and its polar opposite, El Niño, which typically heralds drought in these parts.

Read more: Explainer — El Niño’s impact and what to expect from La Niña

In a linked blog post, the CPC said that it’s “very likely this La Niña will be weak”.

La Niña is triggered by a cooling of surface temperatures in the central and eastern Pacific at tropical latitudes and the current one has been late to the party. Initial forecasts were calling for its emergence in July 2024 and some forecasters in recent months had all but written it off.

Read more: La Niña remains missing in action, Australian forecasters all but write it off

Still, better late than never, and Gauteng as well as much of the wider summer grain belt have certainly been getting decent rainfall over the past few weeks. In 2025 to date, this correspondent’s rain gauge in Johannesburg recorded more than 120mm. 

“Encouragingly, it started to rain in most regions of the country from mid-December 2024 to January 2025 and continues to rain,” Wandile Sihlobo, chief economist at the Agricultural Business Chamber, said in his weekly market update on Monday.

Good summer rainfall this season is crucial after last year’s searing El Niño – caused by a warming of surface temperatures in the eastern Pacific – wreaked havoc on the staple maize and other summer crops in this region.

South Africa’s economy shrank 0.3% in the third quarter (Q3) of last year because of an almost 30% quarterly plunge in output in the agricultural sector. Effectively, El Niño tipped the economy into a contraction, underscoring the impact that climate can have on the economy.

Read more: SA’s GDP growth wilts as agriculture suffers fall of almost 30%

South Africa’s maize harvest fell 23% last year to 12.7 million tonnes and supplies are tight, putting unwelcome upward pressure on prices at a time when food inflation has been slowing. Spot maize prices are fetching more than R6,700 a tonne, 55% higher than a year ago.

The Crop Estimates Committee’s first production estimate for this summer’s maize and other crops will be released 27 February and will give the first clear indication of how the stalks are growing in the fields.

In its latest monthly Seasonal Climate Watch for January to May, the South African Weather Service said it expected “above-normal rainfall for parts of the northeastern central and coastal areas during late summer”.

But it also pointedly noted that “below-normal rainfall is predicted over most parts of the summer rainfall areas”.

This could bode ill for the western limb of the summer grain belt in North West and the Free State. 

The latest Climate Watch was released just before Christmas when La Niña’s arrival remained uncertain. In keeping with previous forecasts, the rest of the summer is forecast to be hotter than usual across most of South Africa.

Rains are especially needed in other countries in the region which were far harder hit by last season’s El Niño-inspired drought. Zimbabwe’s maize production fell more than 60% and Zambia’s harvest was halved, while Malawi and Lesotho also suffered heavy losses.

Read more: Loaded for Bear: Hunger in southern Africa reaches historic levels in El Niño’s wake

Read more: It’s official — 2024 warmest year on record globally, first to exceed 1.5°C above pre-industrial level

When La Niña does fade in the coming months back to neutral conditions, the big question will be: what next? With the planet heating up because of fossil fuel use (2024 was officially the hottest year on record) the arrival of the next El Niño is likely to unleash more misery on the region. DM