El Niño Takes Hold: What Argentina's Farm Belt Can Expect
The El Niño phenomenon has entered its active phase, with a strong ocean-atmosphere coupling now in place, according to the latest reports from the Rosario Board of Trade (BCR), Argentina's leading agricultural exchange. The sea surface temperature anomaly in the Pacific Ocean has reached 1.8°C, up from 1.25°C just a month ago, a clear sign that a strong event is brewing.
Weather consultant Alfredo Elorriaga of GEA/BCR (the exchange's agricultural climate unit) explained that the oceanic phase began in June, but now the atmosphere is fully synchronizing with the warming Pacific. This means the effects on Argentina's weather are already starting to be felt. He compared the situation to the 2015/16 El Niño, which peaked at 2.8°C and is considered one of the strongest in the last 50 years.
However, this season brings greater uncertainty, partly due to a change in methodology at the U.S. National Oceanic and Atmospheric Administration (NOAA) and challenges in accessing data. Projections suggest a peak ranging from 2 to 3 degrees, with a more likely scenario below 2.5.
The Algorithm That Predicts Rainfall
The BCR and its GEA team have updated an algorithm first developed in 2023, which uses data from 36 weather stations in its network and information from 10 global climate models. The result is a statistical estimate of expected rainfall for the key spring months:
| Month | Estimated Increase | Main Impact |
|---|---|---|
| October | +30% | Start of first-crop soybean planting |
| November | +70% | Second-crop soybean planting & late maize |
| December | +90% | Peak of phenomenon: wheat harvest and more planting |
The peak is expected during the last three months of the year. According to the specialist, rains will become more frequent, shortening the work windows available in the fields. This raises a critical question for farmers: how to avoid losing the planting and harvesting windows.
Wheat Harvest and Summer Crop Planting
The heavy rains arrive at a critical moment in the agricultural calendar. In October, first-crop soybean planting begins. In late November, wheat harvest, second-crop soybean planting, and late maize planting all overlap. December looks to be the most complicated month, with 90% more rain than average and a high frequency of precipitation, which could lead to waterlogged soils and severe bottlenecks in field work.
Late maize (late-planted corn) appears as the most vulnerable crop: it is highly sensitive to waterlogging, and its seed is expensive, so any loss during planting has a major economic impact. In a comparison with the 2015/16 El Niño, the peak then occurred in January-February, and Argentina ended up losing 6 million tonnes of soybeans due to excessive water in April.
• Bring forward early maize planting (late August/early September).
• Advance fieldwork whenever possible, do not postpone tasks.
• Make the most of every window of good weather, especially towards late November and December.
Temperature and Heatwaves
El Niño is not just about rain; it also brings rising temperatures. The winter of 2015, during a strong event, was the warmest in Argentina in 60 years. This year, with the ocean-atmosphere coupling, a moderate end to winter is expected. Heatwaves are more frequent in El Niño years, as seen in January of 2023/24, which means summer crops will need careful monitoring.
The Atlantic and Uncertainty
The behavior of the Atlantic Ocean is also playing a role. It is currently warmer than normal and provided extra humidity in July, which brought warm air into the region. However, models now project a cold anomaly for October, November, and December, which would reduce extra moisture from the east. This could help moderate some of the predicted heavy rainfall volumes.
The BCR estimates are a vital reference for farmers making critical decisions. The 2026/27 season is shaping up to be one of the most challenging and potentially productive in recent years, with high water availability but a work pace that will demand efficiency from every farm operation.
Sources: GEA – Rosario Board of Trade (BCR) | La Capital