Ocean · Pacific
El Niño, La Niña
The Niño 3.4 box (5° S–5° N, 170° W–120° W) takes on the colour of the ONI month after month over the last twelve years: red for El Niño (≥ +0.5 °C), blue for La Niña (≤ −0.5 °C).
- Month
- —
- ONI
- —
- El Niño
- La Niña
Latest ONI (3-month season)
2.16 °C
Current state
El Niño
Latest Niño 3.4 anomaly
2.09 °C
Oceanic Niño Index (NOAA CPC) · U.S. Government work, public domain · 10/23/26
Box colour: NOAA CPC ONI (three-month running mean), ±2 °C scale.
Latest ONI (3-month season)
2.16 °C
2026-08
Oceanic Niño Index (NOAA CPC) · U.S. Government work, public domain · 10/23/26
Latest Niño 3.4 anomaly
2.09 °C
2026-09
provisional value
Niño 3.4 SST anomaly (NOAA PSL, ERSSTv5) · U.S. Government work, public domain · 10/23/26
Latest SOI
-4.0
2026-07
provisional value
Southern Oscillation Index (CPC via NOAA PSL) · U.S. Government work, public domain · 10/23/26
Highest ONI of the series
2.6 °C
2015-12
El Niño 2015–2016 / 1997–1998
Oceanic Niño Index (NOAA CPC) · U.S. Government work, public domain · 10/23/26
ONI index since 1950
Oceanic Niño Index (NOAA CPC) · U.S. Government work, public domain · 10/23/26
Show the data as a table
Niño 3.4 anomaly and Southern Oscillation Index since 1990
Niño 3.4 SST anomaly (NOAA PSL, ERSSTv5) · U.S. Government work, public domain · 10/23/26
Southern Oscillation Index (CPC via NOAA PSL) · U.S. Government work, public domain · 10/23/26
Show the data as a table
Multivariate ENSO Index v2 since 1979
Multivariate ENSO Index v2 (NOAA PSL) · U.S. Government work, public domain; cite Zhang et al. (2019) · 10/23/26
Show the data as a table
Method and sources
The four indices are read as published by NOAA CPC and PSL. ONI is NOAA’s operational reference; its base periods (centred 30-year periods updated every five years) remove the warming trend. The PSL Niño 3.4 anomaly uses the 1991–2020 climatology, so the two are not identical.
The last two months are flagged provisional because the providers revise them as observations arrive.
Reading these data
ENSO is a coupled ocean–atmosphere mode of the tropical Pacific; no link with the Sun, earthquakes or magnetic poles is established. Length of day varies with ENSO through angular momentum exchange (see Correspondences).
SOURCES OF THIS PAGE
- Oceanic Niño Index (NOAA CPC)
-
NOAA CPC, Oceanic Niño Index (ONI): 3-month running mean of ERSSTv5 SST anomalies in the Niño 3.4 region, centred 30-year base periods updated every 5 years.
· source page ↗
Licence : U.S. Government work, public domain · retrieved on Oct 23, 2026 · SHA-256 5d6fa3a2f857… - Niño 3.4 SST anomaly (NOAA PSL, ERSSTv5)
-
NOAA PSL, Niño 3.4 index: monthly SST anomaly (5°N–5°S, 170°–120°W) from ERSSTv5, climatology 1991–2020.
· source page ↗
Licence : U.S. Government work, public domain · retrieved on Oct 23, 2026 · SHA-256 879cf3cb31d7… - Southern Oscillation Index (CPC via NOAA PSL)
-
NOAA CPC Southern Oscillation Index (standardised Tahiti − Darwin sea level pressure difference), distributed by NOAA PSL.
· source page ↗
Licence : U.S. Government work, public domain · retrieved on Oct 23, 2026 · SHA-256 dbf3126ccf9e… - Multivariate ENSO Index v2 (NOAA PSL)
-
Zhang, T., Hoell, A., Perlwitz, J., Eischeid, J., Murray, D., Hoerling, M., & Hamill, T. M. (2019). Towards probabilistic multivariate ENSO monitoring. Geophysical Research Letters, 46, 10532–10540.
· doi:10.1029/2019GL083946 · source page ↗
Licence : U.S. Government work, public domain; cite Zhang et al. (2019) · retrieved on Oct 23, 2026 · SHA-256 5bb93aa5564b…