This is the monthly relative sea surface temperature anomaly in the Niño-3.4 region (5°N–5°S, 170°W–120°W). The relative index accounts for tropical ocean warming. These monthly values are not the three-month RONI used for ENSO classification.
About the data
NOAA CPC OISST v2.1, using the 1991–2020 baseline. Data through September 2026. Checked against NOAA on 3 October 2026. Automatically checked every Wednesday at 12:00 pm GMT+8.