November 2025 Climate Forecast Discussion for the period Dec-Feb through Mar-May 2026
**Note: ** The CCSR/IRI seasonal forecasts of precipitation and temperature issued this month are based on an objective calibration procedure that combines four models NCEP-CFSv2, CanSIPS-IC4, COLA-RSMAS-CESM1, and NASA-GEOSS2S models. The climatological base period for normal is 1991-2020. The SST anomalies cited below refer to the OISST.v2.1 SST data set. Starting from June 2024, the observed climatology used to compute the dry mask was updated to 1991-2020, and the criterion modified to mask points where 10% of the training sample (i.e. 3 or more years) received less than or equal to 1 mm over a 3-month season.
During October 2025, sea surface temperature (SST) anomalies remained close to the La Niña threshold over the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 anomaly index at -0.48 °C. Weekly averaged SST anomalies in the Niño 3.4 region were -0.7 °C for the week centered on November 5, 2025, indicating the persistence of cooler sea surface temperatures. The early November CPC ENSO forecast, maintained a “La Nina Advisory”. According to the statement, La Niña conditions are present and are favored to persist through December 2025 – February 2026, with a 61% chance of transitioning to ENSO-neutral conditions during January–March 2026. The Indian Ocean Dipole (IOD) index is negative and is expected to remain so over the next couple of months. Meanwhile, the North Atlantic Ocean continues to exhibit slightly warm SST anomalies, although they have decreased substantially. Additionally, the Pacific Decadal Oscillation (PDO) Index recorded a value of -2.40 in October, following a stronger negative value of -3.23 in August and a record-breaking low of -4.12 in July 2025.
The CCSR/IRI Multi-Model Probability Precipitation Forecast for December–February (DJF) 2026 indicates increased likelihoods of above-normal precipitation (green/blue shading) across Central America, northern South America, equatorial Africa, western and northern Australia, and Indonesia, and of below-normal precipitation (yellow to brown shading) over Mexico, the western and southern United States, around Uruguay, western Africa, the Mediterranean, and eastern China. Going forward into January–March, these probabilities become muted, that is, reduced in strength for both above-normal and below-normal precipitation, and we mostly see climatological odds or very weak probability values across the globe, which is also evident in the February–April and March-May 2026 forecasts. The muted forecasts beyond the boreal winter is consistent with a weaker ENSO signal, with borderline La Niña conditions expected to transition to ENSO-neutral at the start of 2026 and remain so throughout the current forecast period.
The temperature forecasts indicate that above-normal temperatures (red shading) are highly probable in nearly all seasons across much of North America, northern and central Eurasia, the Middle East, and large portions of Africa and South America. Regions with gray shading, notably portions of South America, Africa, and Australia, reflect areas where the probability of the normal temperature category is dominant, indicating outcomes close to the climatological median.
