Has the La Niña weather pattern faded and if not, how long will it last?

As summer fades in South Africa, a burning question on the minds of many a farmer is how long the La Niña weather pattern will last and when will its dreaded El Niño sibling bare its fangs again?

It is a question ripe with implications for food security, inflation and the wider economy, and the ultimate answer to it will either reap rich yields from the fields or a harvest of sorrow.

To wit, the general view among global weather forecasters is that La Niña – which typically brings good rains to this region – formed in December but is weak and will be short-lived. 

But not everyone is on board. Australia’s Bureau of Meteorology in an update last week said La Niña was dead in the water.

“The El Niño-Southern Oscillation (Enso) remains neutral despite a brief period from December to February when the tropical Pacific shifted towards a La Niña-like state,” the bureau said.

Enso refers to the global climate dance that moves to the beat of sea surface temperatures (SSTs) in the tropical latitudes of the central and eastern Pacific. When those temperatures cool, La Niña forms, raising the prospects for rain in southern Africa. 

When they heat up, El Niño takes centre stage, and that generally heralds drought in these parts – which was the case late last summer, when critical grain crops across the region were scorchingly hammered. 

Between these two extremes, Enso is regarded as neutral and the Australians are saying that is the current state of play.

“SSTs in the central tropical Pacific have risen over the past four weeks, with the most recent value of Niño3.4 (−0.30°C for the week ending 2 March) firmly within the neutral range,” the bureau said. 

“The bureau’s model predicts neutral Enso (neither El Niño nor La Niña) until at least July. This is consistent with all surveyed international models.” 

If this is correct, what happens after July will be crucial. 

The Earth Institute at Columbia University sees Enso in a neutral phase by April with a more than 50% prospect of it remaining until August. 

But by September, it sees a switch back to La Niña – just in time for the southern hemisphere spring, with the end of the calendar year having a 55% chance of it remaining in place.

Pointedly, it sees only a 13% chance of El Niño conditions being in place by the end of 2025, with a 32% chance of the year finishing in neutral – which can mean normal rainfall in this region.

The Columbia forecast is the one favoured as the most accurate by the Agricultural Business Chamber of SA (Agbiz).

“We are currently in a favourable agricultural season, a recovery from the drought of 2023-24 production year. It is still early to tell what the next season would look like, but the early estimates we monitor suggest that we may have yet another season of abundance in [the] 2025-26 production year that starts in October this year,” Agbiz chief economist Wandile Sihlobo told Daily Maverick. 

El Niño, it must be said, does figure more prominently later in 2025 in other reports and predictions and it is too early to forecast what Christmas will bring.

But for now, the signs are tentatively hopeful for the remainder of the summer crop season and the start of the next one a few months’ hence.

With hunger and food security still a major concern in the region – notably in Zimbabwe, Zambia and Malawi, but also in South Africa – hopefully La Niña will bounce back before El Niño. DM