July 2026 Climate Forecast Discussion for the period August-October 2026 through November-January 2026-2027
**Note: ** The CCSR/IRI seasonal forecasts of precipitation and temperature issued this month are based on an objective calibration procedure that combines the output from five models: NCEP-CFSv2, CanSIPS-IC4, COLA-RSMAS-CESM1, GFDL-SPEAR and NASA-GEOSS2S-2. 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 June 2026, sea surface temperature (SST) anomalies increased further across the central-eastern equatorial Pacific Ocean, with the monthly Niño 3.4 index reaching +1.55 °C. The most recent weekly Niño 3.4 index value (centered on 8 July 2026) reached +2.0°C, indicating that El Niño has continued to intensify and confirming the presence of strong El Niño conditions across the tropical Pacific. The CPC ENSO forecast, issued in early July under an "El Niño Advisory," indicates that El Niño is expected to persist and strengthen through the end of the year, with a 97% probability of continuing into early spring 2027. (It is important to note that ENSO monitoring and prediction issued by CPC is now based on the relative Niño 3.4 index). The Indian Ocean Dipole (IOD) index is currently in a neutral state. The North Atlantic registered a value of +0.17 °C, while the South Atlantic showed gradually increasing warming, reaching +0.32 °C in June 2026. The Pacific Decadal Oscillation (PDO) index recorded a value of -1.34 °C in June 2026.
The CCSR/IRI Objective Multi-Model Probability Precipitation Forecast for August–October (ASO) 2026 indicates substantially increased probabilities of below-normal precipitation (yellow to brown shading) across northern South America, Central America and the Caribbean, the Indian Peninsula, parts of Australia, and the Maritime Continent. This dry signal persists through September–November (SON), October–December (OND), and November–January (NDJ), although its intensity and spatial extent vary by region. During SON, an area of enhanced probability for below-normal precipitation develops over southern Africa and strengthens further during OND and NDJ. By OND and NDJ, increased odds of below-normal precipitation also extend across the northern and northeastern United States and Canada. In contrast, during ASO, the southwestern United States and the adjacent Southern Plains exhibit increased probabilities of above-normal precipitation. This wet signal expands eastward and intensifies across the southern United States during SON, OND, and NDJ. From ASO through NDJ, probabilities also favor above-normal precipitation over Uruguay and central Chile, as well as parts of northeast Africa, the Middle East, and Southwest Asia. Many of these precipitation patterns are broadly consistent with the evolution of El Niño conditions in the central and eastern tropical Pacific, which are forecast to strengthen and peak during the fall of 2026. However, not all regional precipitation anomalies can be directly attributed to ENSO, as other modes of climate variability and regional processes may also influence these patterns.
The temperature forecasts indicate a high likelihood of above-normal temperatures (red shading) across much of North America, northern and central Eurasia, the Middle East, Asia, the Maritime Continent, and large parts of Africa and South America throughout the forecast period. During the October–December (OND) and November–January (NDJ) seasons, areas of increased probability for below-normal temperatures (blue shading) emerge over parts of southern South America, particularly central Argentina and surrounding regions, as well as across portions of central and southwestern Asia.
