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.
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.
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.
43% is the estimated probability of an extraordinary Coastal El Niño in the Niño 1+2 region during the summer from December 2026 to March 2027.
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.
58% or higher is the probability that El Niño will reach very strong magnitude in the Niño 3.4 region between September 2026 and January 2027.
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.
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.
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.
66.57% was represented by the 1,343.89 million cubic meters of water stored in Dominican Republic reservoirs on August 21, 2026, according to INDRHI data.
