As was the case last winter, there is still no clarity on whether a La Niña system can be expected in the coming summer rainfall season.
By Alani Janeke
Forecasts suggest that sea surface temperatures may cool down or lean slightly towards La Niña trends by September this year, although these temperatures are currently very close to the long-term average and therefore cannot indicate clear patterns.
“Just like the previous season, no clear trends will emerge and the sea surface temperatures will likely range between neutral and weak La Niña tendencies,” says independent agricultural meteorologist Johan van den Berg.
He explains that the timing of the shift this year will be significant.
“Should La Niña tendencies occur in September and October, as predictions currently suggest, the rains might start slightly earlier compared with last season, especially eastward.
“In a scenario where neutral or weak La Niña tendencies occur, lower rainfall is likely in the first part of the season, and wetter conditions in the second part.”
Yields In Similar Seasons
In the past, the country’s maize yields during neutral to weak La Niña seasons have been at least average to above average, with one or two exceptions.
“A classic example is the 2024-25 season, which started with relatively poor soil water conditions and farmers struggling significantly with timely planting,” says Van den Berg. “The wet middle to second part of the season pulled the harvest through with very good yields in certain areas – although there were patches, such as in the southwest Free State and adjacent parts of North West, where drought damage occurred.”
During El Niño-leaning seasons, rainfall is higher in the first part of the season, whereas the second part of the season, particularly February and March, tends to be drier.
Groundwater Levels And Waterlogging
After heavy rainfall towards the end of the 2024-25 season, summer grain producers can look forward to favourable groundwater levels for the 2025-26 season. This will aid them in planting within the planting window.
“However, the possibility of a dry period in November and December could pose a risk for those who plant too early,” Van den Berg says.
“The big balancing act will be to plant before it gets too wet in the second part of the season, but not so early that drought damage occurs.”
For planning purposes, he says, there is a good chance of at least average yields in the coming summer rainfall season, provided the forecasts are accurate. Improved yields may even be possible.
“Waterlogging can once again pose significant risks in the coming season, especially in areas prone to the phenomenon, and particularly where substantial groundwater has already accumulated following the past summer.”
