El Nino Watch

ENSO Indices Today: ONI, RONI, Nino 3.4, SOI, MEI

Name: Multivariate ENSO Index version 2 (MEI.v2), bi-monthly since 1979
Creator: NOAA Physical Sciences Laboratory
License: https://www.noaa.gov/information-technology/open-data-dissemination

Every ENSO index with its latest value and history: NOAA ONI and RONI, weekly Nino 1+2, 3, 3.4 and 4 anomalies, SOI (CPC and BoM), MEI.v2 and global SST.

Latest values

Index	Latest	Period	Previous
ONI (Oceanic Nino Index)	+1.80 °C	JJA 2026	+1.39
RONI (Relative Oceanic Nino Index)	+1.36 °C	JJA 2026	+0.97
Nino 3.4 weekly SST anomaly	+3.00 °C	week of 16 Sep 2026	+2.90
Nino 3.4 weekly SST	+29.60 °C	week of 16 Sep 2026	+29.60
SOI (Southern Oscillation Index, CPC)	-1.10	Aug 2026	-2.40
SOI (BoM, Troup)	-14.60	Aug 2026	-29.10
MEI.v2 (Multivariate ENSO Index)	+2.54	AS 2026	+2.41
World sea surface temperature	+21.14 °C	23 Sep 2026	+21.14

Status

ONI (NOAA CPC): +1.80 °C, JJA 2026 (previous +1.39 °C)
RONI (NOAA CPC): +1.36 °C, JJA 2026
Nino 3.4 weekly (NOAA CPC / OISST): +3.0 °C anomaly, week of 16 Sep 2026 (SST 29.6 °C)
NOAA CPC ENSO status: El Niño Advisory (issued 10 Sep 2026), El Niño is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27. source
IRI ENSO probabilities (issued 21 Sep 2026): SON: El Nino 100%, neutral 0%, La Nina 0%; OND: El Nino 100%, neutral 0%, La Nina 0%; NDJ: El Nino 100%, neutral 0%, La Nina 0%; DJF: El Nino 100%, neutral 0%, La Nina 0%
Koh Samui watch level: Prepare (evaluated 25 Sep 2026 14:19 UTC)
Data updated: 25 Sep 2026 14:19 UTC