AO Index | AMOC Index | ENSO | EPO Index | MEIv2 Index | NAO Index | PDO Index | PNA Index | QBO Index | Teleconnection Monthly Summary

1950's | 1960's | 1970's | 1980's | 1990's | 2000's | 2010's | 2020's

ENSO and Snowfall Earth | 1960's | 1970's | 1980's | 1990's | 2000's | 2010's | 2020's

MEIv2 Index

Link to MEIv2 Correlation

The El Niño/Southern Oscillation (ENSO) - a naturally occurring anomalous state of tropical Pacific coupled ocean-atmosphere conditions - is the primary predictor for global climate disruptions. These can persist over several seasons and thereby produce severe regional effects. An appraisal of the real-time status of ENSO is thus important for a host of climate services that inform societal responses and trigger policy actions for water supply, food security, health, and public safety. The MEI, which combines both oceanic and atmospheric variables, facilitates in a single index an assessment of ENSO. It especially gives real-time indications of ENSO intensity, and through historical analysis - provides a context for meaningful comparative study of evolving conditions.


The bi-monthly Multivariate El Niño/Southern Oscillation (ENSO) index (MEI.v2) is the time series of the leading combined Empirical Orthogonal Function (EOF) of five different variables (sea level pressure (SLP), sea surface temperature (SST), zonal and meridional components of the surface wind, and outgoing longwave radiation (OLR)) over the tropical Pacific basin (30°S-30°N and 100°E-70°W). The EOFs are calculated for 12 overlapping bi-monthly "seasons" (Dec-Jan, Jan-Feb, Feb-Mar,..., Nov-Dec) in order to take into account ENSO's seasonality, and reduce effects of higher frequency intraseasonal variability.


The MEIv2 was discontinued for a while, but is now being produced again.




MEIv2 Index by Year

MEIv2 evolution of current ENSO event in historical content


MEI Values by Year

Historical MEI.v2 Values Updated: 7/13/2026
Year DJ JF FM MA AM MJ JJ JA AS SO ON ND AVG
1979 0.47 0.27 -0.04 0.26 0.35 -0.14 -0.13 0.50 0.42 0.28 0.58 0.68 0.29
1980 0.42 0.30 0.52 0.85 0.71 0.55 0.52 0.13 0.19 0.06 -0.09 -0.09 0.34
1981 -0.28 -0.19 0.16 0.15 -0.38 -0.63 -0.51 -0.25 0.03 -0.05 -0.16 -0.18 -0.19
1982 -0.44 -0.61 -0.31 0.13 0.66 1.42 1.87 1.93 1.74 1.87 2.25 2.45 1.08
1983 2.59 2.73 2.71 2.74 2.60 1.58 0.88 0.03 -0.41 -0.44 -0.42 -0.44 1.18
1984 -0.38 -0.36 -0.06 -0.06 -0.78 -0.75 -0.23 -0.02 -0.06 -0.01 -0.59 -0.32 -0.30
1985 -0.31 -0.57 -0.51 -0.68 -1.04 -0.24 -0.02 -0.36 -0.35 0.05 0.11 -0.36 -0.36
1986 -0.42 -0.33 -0.37 -0.30 0.24 0.61 0.77 1.24 1.38 0.57 0.73 1.07 0.43
1987 0.96 1.12 1.49 1.62 1.85 1.78 1.74 1.49 1.18 1.05 0.89 0.86 1.34
1988 0.64 0.39 0.27 -0.13 -0.59 -1.35 -1.77 -1.82 -1.80 -1.53 -1.65 -1.56 -0.91
1989 -1.15 -1.14 -1.26 -1.09 -0.98 -1.04 -1.11 -0.74 -0.60 -0.59 -0.35 -0.14 -0.85
1990 0.13 0.40 0.47 0.12 0.07 0.15 0.27 0.11 0.26 -0.06 0.07 0.26 0.19
1991 0.13 0.04 0.21 0.49 0.74 1.07 0.85 0.41 0.65 1.17 1.14 1.23 0.68
1992 1.63 1.51 1.69 2.00 1.71 1.66 0.82 0.13 0.56 0.95 0.84 0.77 1.19
1993 0.91 1.00 0.85 1.05 1.40 1.11 0.73 0.57 0.63 0.93 0.72 0.27 0.85
1994 0.06 -0.09 -0.02 0.19 0.17 0.40 0.93 0.86 1.03 1.52 0.93 0.80 0.57
1995 0.75 0.53 0.21 0.34 0.39 -0.08 -0.27 -0.59 -0.78 -0.57 -0.62 -0.85 -0.13
1996 -0.78 -0.71 -0.63 -0.78 -0.93 -0.70 -0.59 -0.50 -0.18 -0.29 -0.18 -0.46 -0.56
1997 -0.83 -0.89 -0.41 0.39 1.15 2.35 2.07 2.27 2.16 1.93 1.95 2.00 1.18
1998 2.24 2.43 2.26 2.25 1.72 -0.25 -1.53 -1.79 -1.39 -1.19 -1.27 -1.20 0.19
1999 -1.17 -1.11 -1.04 -1.20 -1.42 -1.26 -1.21 -1.12 -1.16 -1.33 -1.36 -1.40 -1.23
2000 -1.22 -1.24 -1.38 -1.03 -1.17 -1.12 -0.55 -0.17 -0.34 -0.50 -0.77 -0.75 -0.85
2001 -0.81 -0.82 -0.75 -0.74 -0.78 -0.57 -0.02 0.23 -0.09 -0.28 -0.36 -0.07 -0.42
2002 -0.07 -0.41 -0.26 -0.36 -0.06 0.42 0.39 0.81 0.74 0.72 0.72 0.79 0.29
2003 0.70 0.56 0.57 -0.04 -0.51 -0.22 -0.07 -0.04 0.14 0.30 0.36 0.18 0.16
2004 0.12 -0.15 -0.50 -0.29 -0.38 -0.05 0.37 0.69 0.51 0.30 0.44 0.49 0.13
2005 0.10 0.56 0.75 0.13 0.14 0.14 -0.08 -0.03 -0.08 -0.80 -0.80 -0.72 -0.06
2006 -0.67 -0.50 -0.58 -0.77 -0.30 -0.06 0.15 0.57 0.63 0.62 0.83 0.56 0.04
2007 0.61 0.46 -0.13 -0.47 -0.65 -0.98 -0.65 -0.90 -1.15 -1.19 -1.19 -1.27 -0.63
2008 -1.12 -1.24 -1.57 -1.27 -0.96 -0.81 -0.94 -0.99 -1.01 -1.15 -1.13 -1.08 -1.11
2009 -0.99 -0.88 -0.89 -0.68 -0.63 0.25 0.58 0.54 0.41 0.61 1.18 1.06 0.05
2010 1.03 1.34 1.28 0.42 -0.47 -1.70 -2.45 -2.45 -2.41 -2.21 -2.08 -1.94 -0.97
2011 -1.86 -1.64 -1.82 -1.86 -1.35 -1.13 -0.87 -0.89 -1.18 -1.43 -1.33 -1.24 -1.38
2012 -1.12 -0.71 -0.56 -0.48 -0.40 -0.14 0.37 0.03 -0.27 -0.25 -0.17 0.00 -0.31
2013 0.00 -0.04 -0.17 -0.44 -0.87 -1.11 -0.79 -0.46 -0.37 -0.20 -0.16 -0.26 -0.41
2014 -0.49 -0.45 -0.19 -0.24 -0.26 -0.02 0.39 0.21 -0.09 0.04 0.30 0.32 -0.04
2015 0.17 -0.04 0.06 0.52 1.22 1.74 1.66 1.85 2.14 2.12 1.87 1.94 1.27
2016 1.90 1.75 1.30 1.23 1.15 0.16 -0.51 -0.21 -0.28 -0.47 -0.30 -0.16 0.46
2017 -0.23 -0.25 -0.47 -0.36 -0.10 -0.57 -0.86 -0.89 -0.84 -0.62 -0.54 -0.68 -0.53
2018 -0.76 -0.75 -0.92 -1.35 -0.89 -0.61 -0.34 0.13 0.49 0.38 0.19 0.13 -0.36
2019 0.04 0.46 0.71 0.29 0.20 0.28 0.20 0.26 0.13 0.22 0.44 0.40 0.30
2020 0.22 0.13 0.09 -0.14 -0.36 -0.87 -0.88 -0.94 -1.21 -1.19 -1.14 -1.16 -0.62
2021 -1.18 -0.93 -0.81 -1.04 -1.16 -1.29 -1.53 -1.35 -1.45 -1.50 -1.43 -1.19 -1.24
2022 -1.06 -0.96 -1.28 -1.76 -1.88 -2.07 -2.10 -1.79 -1.76 -1.71 -1.48 -1.25 -1.59
2023 -1.11 -0.81 -0.67 -0.41 -0.14 0.23 0.25 0.43 0.59 0.26 0.64 1.10 0.03
2024 0.70 0.70 0.80 0.30 0.10 -0.20 -0.70 -0.70 0.60 0.50 0.70 0.90 0.31
2025 -1.00 0.80 -0.70 -0.40 -0.40 -1.20 -1.20 -0.90 -1.10 -1.20 -1.10 -0.80 -0.77
2026 -0.80 -0.90 -1.00 -0.60 0.30 1.50             -0.25
Year DJ JF FM MA AM MJ JJ JA AS SO ON ND AVG
Warm (red) and cold (blue) periods based on a threshold of +/- 0.5
Data: https://psl.noaa.gov/enso/mei/