NOAA confirms strengthening El Niño, with 81% chance of very strong conditions in October–December 2026

El Niño is present and strengthening across the central and eastern equatorial Pacific, NOAA Climate Prediction Center (CPC) confirmed on August 3. An El Niño Advisory remains in effect, with NOAA assigning an 81% chance of very strong conditions during October–December 2026. Currently, El Niño has a 97% chance of continuing through early Northern Hemisphere spring 2027. NOAA defines a very strong event as a Relative Oceanic Niño Index, or RONI, of at least 2°C (3.6°F). RONI starts with the Niño 3.4 sea-surface temperature departure, subtracts the average tropical departure, adjusts the variance and applies a three-month running mean. NOAA listed the April–June 2026 RONI at 0.5°C (0.9°F), its operational El Niño threshold. The agency warns that a stronger El Niño does not automatically produce larger weather and climate impacts. Greater strength raises the probability of some impacts but does not determine their magnitude. The latest weekly sea-surface temperature departures reached 3.2°C (5.8°F) in the Niño 1+2 region, 2.1°C (3.8°F) in Niño 3, 1.5°C (2.7°F) in Niño 3.4 and 0.2°C (0.4°F) in Niño 4. The strongest warming remained in the eastern equatorial Pacific, while the Niño 4 region farther west recorded a much smaller departure. Above-average temperatures extended from the Date Line to the eastern Pacific during the four weeks ending August 1. Warming increased across parts of the east-central and eastern Pacific, while temperatures weakened relative to average in the west-central Pacific and near Indonesia. The World Meteorological Organization (WMO) reported a rapid rise in the Niño 3.4 anomaly during the Northern Hemisphere spring and early summer. The anomaly increased from 0.5°C (0.9°F) in April to 0.9°C (1.6°F) in May and 1.6°C (2.9°F) in June, based on the 1991–2020 average. The April–June mean was 1°C (1.8°F). WMO’s multimodel forecast shows further strengthening during August–October 2026. The forecast Niño 3.4 mean rises from 2.7 ± 0.2°C (4.9 ± 0.4°F) in August to 3.1 ± 0.4°C (5.6 ± 0.7°F) in September and 3.4 ± 0.6°C (6.1 ± 1.1°F) in October. The three-month mean is forecast at 2.9 ± 0.4°C (5.2 ± 0.7°F), with the development trajectory reaching its highest point in November. Above-normal temperatures are favored across most land areas north of 60°S during August–October. The main warm signals cover much of Africa, southern Europe, the Arabian Peninsula, the Indian subcontinent, eastern Asia, western North America below 60°N, Central America and the Caribbean. Warm conditions are also favored across southern Africa, tropical and subtropical South America, New Zealand, and southern and central Australia. The forecast signal is weaker over parts of northern Asia and northwestern and eastern North America.