January 2026 Climate Forecast Discussion

January 2026 Climate Forecast Discussion for the period Feb-Apr through May-Jul 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, GFDL-SPEAR, 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 December 2025, sea surface temperature (SST) anomalies remained in La Niña territory across the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 index at -0.61 °C. This marked the second consecutive month that SST anomalies persisted below the La Niña threshold value. Weekly averaged SST anomalies in the Niño 3.4 region were -0.8 °C for the week centered on January 7, 2026, indicating the persistence of cooler sea surface temperatures. The early January CPC ENSO forecast, maintained an “La Nina Advisory”, with La Niña favored to continue for the next month or two, and with a transition to ENSO-neutral likely in January-March 2026 (68% chance). The Indian Ocean Dipole (IOD) index is currently within the neutral range 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. The Pacific Decadal Oscillation (PDO) Index recorded a value of -1.01 °C in December 2025.

The CCSR/IRI Multi-Model Probability Precipitation Forecast for Feb–Apr (FMA) 2026 indicates slightly elevated odds of above-normal precipitation (green/blue shading) across parts of the northeastern United States, Central America, northern South America, equatorial Africa, parts of the Arabian Peninsula, and northeastern Australia. The outlook also shows increased likelihoods of below-normal precipitation (yellow to brown shading) over Mexico, the western and southern United States, around Uruguay, parts of Central and Southwest Asia, eastern China, and the Maritime Continent. In subsequent seasons (Mar–May, Apr–Jun, and May–Jul), these signals weaken, with much of the globe reverting to near-climatological probabilities or only very small departures from equal chances. These muted forecast signals are to be expected given the weakening ENSO influence, with La Niña expected to transition to ENSO-neutral during January–March 2026.

The temperature forecasts indicate that above-normal temperatures (red shading) are highly probable in most seasons across much of North America, northern and central Eurasia, the Middle East, and large portions of Africa and South America. In Feb–Apr, areas of below-normal temperatures (blue shading), notably in parts of western Canada, are evident; by Mar–May these areas transition toward near-normal conditions. In the later seasons (Apr–Jun and May–Jul), parts of southern and southeastern Australia also show enhanced probabilities of below-normal temperatures. Regions shaded gray, including portions of northern South America during Feb–Apr and Mar–May, indicate that the near-normal temperature category is most likely, implying outcomes close to the climatological median.