Data or statistical facts on the situation and perspectives of agri-food systems and the impact of policies
From October 5 to 11, 2026, every region of Costa Rica is forecast to receive below-normal rainfall. The IMN estimates an extreme-event probability of about 20%, although it reports high uncertainty for this final week of the outlook.
During the four weeks from September 14 to October 11, 2026, the IMN forecasts below-normal rainfall in Costa Rica's Pacific region, Central Valley, and Western Northern Zone. The pattern is expected to be associated with El Niño and stronger-than-usual trade winds.
Between 30 and 155 mm of rain could accumulate in Costa Rica's Northern Zone from September 14 to 20, 2026, the highest forecast range among the country's regions. The probability of an extreme event is low, at about 25%, and forecast uncertainty is also low.
In July 2026, the Niño3.4 index exceeded a +2°C sea-surface temperature anomaly in the equatorial Pacific, a threshold that Météo-France classifies as strong El Niño intensity.
Among the most intense episodes observed since 1950 could be the 2026 El Niño: six-month seasonal forecasts indicate that the Niño3.4 index will continue rising and peak in late 2026, potentially reaching very strong intensity.
4 low-intensity, short-lived tropical systems had been observed in the 2026 Atlantic season by August 28; only Tropical Storm Dolly occurred in the main development region. Météo-France links this historically low activity to the strong El Niño and high wind shear.
From August 31 to September 27, 2026, Météo-France forecasts rainfall totals clearly below normal across the Leeward Islands of the Lesser Antilles. From September 7 to 27, the rainfall deficit is expected to range from slight to moderate.
Between +0.5°C and +1.5°C above normal are the temperatures forecast from August 31 to September 27, 2026, in Guadeloupe, Saint-Martin, and Saint-Barthélemy.
September 7-13, 2026, is forecast to be the driest of the three weeks from September 7 to 27 and the warmest of the four-week outlook period, particularly in Saint-Martin and Saint-Barthélemy.
62% or higher is the probability that Coastal El Niño will reach extraordinary magnitude in the Niño 1+2 region between September 2026 and January 2027.
