El Niño and La Niña Years and Intensities
Based on Oceanic Niño Index (ONI)
Jan Null, CCM
Updated thru August-September-October 2023
 
The Oceanic Niño Index (ONI) has become the de-facto standard that NOAA uses for classifying El Niño (warm) and La Niña (cool) events in the eastern tropical Pacific.  It is the running 3-month mean SST anomaly for the Niño 3.4 region (i.e., 5oN-5oS, 120o-170oW).  Events are defined as 5 consecutive overlapping 3-month periods at or above the +0.5o anomaly for warm (El Niño) events and at or below the -0.5 anomaly for cool (La Niña) events.  The threshold is further broken down into Weak (with a 0.5 to 0.9 SST anomaly), Moderate (1.0 to 1.4), Strong (1.5 to 1.9) and Very Strong (≥ 2.0) events.  For the purpose of this report for an event to be categorized as weak, moderate, strong or very strong it must have equaled or exceeded the threshold of the highest category for at least 3 consecutive overlapping 3-month periods.
El Niño - 27 La Niña - 25
Weak - 11 Moderate - 8 Strong - 5 Very Strong - 3 Weak - 12 Moderate - 6 Strong - 7
1952-53 1951-52 1957-58 1982-83 1954-55 1955-56 1973-74
1953-54 1963-64 1965-66 1997-98 1964-65 1970-71 1975-76
1958-59 1968-69 1972-73 2015-16 1971-72 1995-96 1988-89
1969-70 1986-87 1987-88   1974-75 2011-12 1998-99
1976-77 1994-95 1991-92   1983-84 2020-21 1999-00
1977-78 2002-03     1984-85 2021-22 2007-08
1979-80 2009-10     2000-01   2010-11
2004-05 2023-24     2005-06  
2006-07       2008-09    
2014-15       2016-17    
2018-19       2017-18    
        2022-23    
             

[Click HERE for full-size image of this graph]

Graph - Oceanic Niño Index (ONI) 1950-present
Graph - Ocean Niño Index (ONI) 1950-1989
Running 3-Month Mean ONI values
https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php
WE=Weak El Niño, ME=Moderate El Niño, SE=Strong El Niño, VSE=Very Strong El Niño
WL=Weak La Niña, ML=Moderate La Niña, SL=Strong La Niña
ENSO Type Season JJA JAS ASO SON OND NDJ DJF JFM FMA MAM AMJ MJJ
  1950-1951 -0.5 -0.4 -0.4 -0.4 -0.6 -0.8 -0.8 -0.5 -0.2 0.2 0.4 0.6
ME 1951-1952 0.7 0.9 1.0 1.2 1.0 0.8 0.5 0.4 0.3 0.3 0.2 0.0
WE 1952-1953 -0.1 0.0 0.2 0.1 0.0 0.1 0.4 0.6 0.6 0.7 0.8 0.8
WE 1953-1954 0.7 0.7 0.8 0.8 0.8 0.8 0.8 0.5 0.0 -0.4 -0.5 -0.5
WL 1954-1955 -0.6 -0.8 -0.9 -0.8 -0.7 -0.7 -0.7 -0.6 -0.7 -0.8 -0.8 -0.7
ML 1955-1956 -0.7 -0.7 -1.1 -1.4 -1.7 -1.5 -1.1 -0.8 -0.6 -0.5 -0.5 -0.5
  1956-1957 -0.6 -0.6 -0.5 -0.4 -0.4 -0.4 -0.2 0.1 0.4 0.7 0.9 1.1
SE 1957-1958 1.3 1.3 1.3 1.4 1.5 1.7 1.8 1.7 1.3 0.9 0.7 0.6
WE 1958-1959 0.6 0.4 0.4 0.4 0.5 0.6 0.6 0.6 0.5 0.3 0.2 -0.1
  1959-1960 -0.2 -0.3 -0.1 0.0 0.0 0.0 -0.1 -0.1 -0.1 0.0 0.0 0.0
  1960-1961 0.1 0.2 0.3 0.2 0.1 0.1 0.0 0.0 0.0 0.1 0.2 0.3
  1961-1962 0.1 -0.1 -0.3 -0.3 -0.2 -0.2 -0.2 -0.2 -0.2 -0.3 -0.3 -0.2
  1962-1963 0.0 -0.1 -0.1 -0.2 -0.3 -0.4 -0.4 -0.2 0.2 0.3 0.3 0.5
ME 1963-1964 0.9 1.1 1.2 1.3 1.4 1.3 1.1 0.6 0.1 -0.3 -0.6 -0.6
WL 1964-1965 -0.6 -0.7 -0.8 -0.8 -0.8 -0.8 -0.6 -0.3 -0.1 0.2 0.5 0.8
SE 1965-1966 1.2 1.5 1.9 2.0 2.0 1.7 1.4 1.2 1.0 0.7 0.4 0.2
  1966-1967 0.2 0.1 -0.1 -0.1 -0.2 -0.3 -0.4 -0.5 -0.5 -0.4 -0.2 0.0
  1967-1968 0.0 -0.2 -0.3 -0.4 -0.3 -0.4 -0.6 -0.7 -0.6 -0.4 0.0 0.3
ME 1968-1969 0.6 0.5 0.4 0.5 0.7 1.0 1.1 1.1 0.9 0.8 0.6 0.4
WE 1969-1970 0.4 0.5 0.8 0.9 0.8 0.6 0.5 0.3 0.3 0.2 0.0 -0.3
ENSO Type Season JJA JAS ASO SON OND NDJ DJF JFM FMA MAM AMJ MJJ
ML 1970-1971 -0.6 -0.8 -0.8 -0.7 -0.9 -1.1 -1.4 -1.4 -1.1 -0.8 -0.7 -0.7
WL 1971-1972 -0.8 -0.8 -0.8 -0.9 -1.0 -0.9 -0.7 -0.4 0.1 0.4 0.7 0.9
SE 1972-1973 1.1 1.4 1.6 1.8 2.1 2.1 1.8 1.2 0.5 -0.1 -0.5 -0.9
SL 1973-1974 -1.1 -1.3 -1.5 -1.7 -1.9 -2.0 -1.8 -1.6 -1.2 -1.0 -0.9 -0.8
WL 1974-1975 -0.5 -0.4 -0.4 -0.6 -0.8 -0.6 -0.5 -0.6 -0.7 -0.7 -0.8 -1.0
SL 1975-1976 -1.1 -1.2 -1.4 -1.4 -1.6 -1.7 -1.6 -1.2 -0.7 -0.5 -0.3 0.0
WE 1976-1977 0.2 0.4 0.6 0.8 0.9 0.8 0.7 0.6 0.3 0.2 0.2 0.3
WE 1977-1978 0.4 0.4 0.6 0.7 0.8 0.8 0.7 0.4 0.1 -0.2 -0.3 -0.3
  1978-1979 -0.4 -0.4 -0.4 -0.3 -0.1 0.0 0.0 0.1 0.2 0.3 0.2 0.0
WE 1979-1980 0.0 0.2 0.3 0.5 0.5 0.6 0.6 0.5 0.3 0.4 0.5 0.5
  1980-1981 0.3 0.0 -0.1 0.0 0.1 0.0 -0.3 -0.5 -0.5 -0.4 -0.3 -0.3
  1981-1982 -0.3 -0.2 -0.2 -0.1 -0.2 -0.1 0.0 0.1 0.2 0.5 0.7 0.7
VSE 1982-1983 0.8 1.1 1.6 2.0 2.2 2.2 2.2 1.9 1.5 1.3 1.1 0.7
WL 1983-1984 0.3 -0.1 -0.5 -0.8 -1.0 -0.9 -0.6 -0.4 -0.3 -0.4 -0.5 -0.4
WL 1984-1985 -0.3 -0.2 -0.2 -0.6 -0.9 -1.1 -1.0 -0.8 -0.8 -0.8 -0.8 -0.6
  1985-1986 -0.5 -0.5 -0.4 -0.3 -0.3 -0.4 -0.5 -0.5 -0.3 -0.2 -0.1 0.0
ME 1986-1987 0.2 0.4 0.7 0.9 1.1 1.2 1.2 1.2 1.1 0.9 1.0 1.2
SE 1987-1988 1.5 1.7 1.6 1.5 1.3 1.1 0.8 0.5 0.1 -0.3 -0.9 -1.3
SL 1988-1989 -1.3 -1.1 -1.2 -1.5 -1.8 -1.8 -1.7 -1.4 -1.1 -0.8 -0.6 -0.4
  1989-1990 -0.3 -0.3 -0.2 -0.2 -0.2 -0.1 0.1 0.2 0.3 0.3 0.3 0.3
ENSO Type Season JJA JAS ASO SON OND NDJ DJF JFM FMA MAM AMJ MJJ
  1990-1991 0.3 0.4 0.4 0.3 0.4 0.4 0.4 0.3 0.2 0.3 0.5 0.6
SE 1991-1992 0.7 0.6 0.6 0.8 1.2 1.5 1.7 1.6 1.5 1.3 1.1 0.7
  1992-1993 0.4 0.1 -0.1 -0.2 -0.3 -0.1 0.1 0.3 0.5 0.7 0.7 0.6
  1993-1994 0.3 0.3 0.2 0.1 0.0 0.1 0.1 0.1 0.2 0.3 0.4 0.4
ME 1994-1995 0.4 0.4 0.6 0.7 1.0 1.1 1.0 0.7 0.5 0.3 0.1 0.0
ML 1995-1996 -0.2 -0.5 -0.8 -1.0 -1.0 -1.0 -0.9 -0.8 -0.6 -0.4 -0.3 -0.3
  1996-1997 -0.3 -0.3 -0.4 -0.4 -0.4 -0.5 -0.5 -0.4 -0.1 0.3 0.8 1.2
VSE 1997-1998 1.6 1.9 2.1 2.3 2.4 2.4 2.2 1.9 1.4 1.0 0.5 -0.1
SL 1998-1999 -0.8 -1.1 -1.3 -1.4 -1.5 -1.6 -1.5 -1.3 -1.1 -1.0 -1.0 -1.0
SL 1999-2000 -1.1 -1.1 -1.2 -1.3 -1.5 -1.7 -1.7 -1.4 -1.1 -0.8 -0.7 -0.6
WL 2000-2001 -0.6 -0.5 -0.5 -0.6 -0.7 -0.7 -0.7 -0.5 -0.4 -0.3 -0.3 -0.1
  2001-2002 -0.1 -0.1 -0.2 -0.3 -0.3 -0.3 -0.1 0.0 0.1 0.2 0.4 0.7
ME 2002-2003 0.8 0.9 1.0 1.2 1.3 1.1 0.9 0.6 0.4 0.0 -0.3 -0.2
  2003-2004 0.1 0.2 0.3 0.3 0.4 0.4 0.4 0.3 0.2 0.2 0.2 0.3
WE 2004-2005 0.5 0.6 0.7 0.7 0.7 0.7 0.6 0.6 0.4 0.4 0.3 0.1
WL 2005-2006 -0.1 -0.1 -0.1 -0.3 -0.6 -0.8 -0.8 -0.7 -0.5 -0.3 0.0 0.0
WE 2006-2007 0.1 0.3 0.5 0.7 0.9 0.9 0.7 0.3 0.0 -0.2 -0.3 -0.4
SL 2007-2008 -0.5 -0.8 -1.1 -1.4 -1.5 -1.6 -1.6 -1.4 -1.2 -0.9 -0.8 -0.5
WL 2008-2009 -0.4 -0.3 -0.3 -0.4 -0.6 -0.7 -0.8 -0.7 -0.5 -0.2 0.1 0.4
ME 2009-2010 0.5 0.5 0.7 1.0 1.3 1.6 1.5 1.3 0.9 0.4 -0.1 -0.6
ENSO Type Season JJA JAS ASO SON OND NDJ DJF JFM FMA MAM AMJ MJJ
SL 2010-2011 -1.0 -1.4 -1.6 -1.7 -1.7 -1.6 -1.4 -1.1 -0.8 -0.6 -0.5 -0.4
ML 2011-2012 -0.5 -0.7 -0.9 -1.1 -1.1 -1.0 -0.8 -0.6 -0.5 -0.4 -0.2 0.1
  2012-2013 0.3 0.3 0.3 0.2 0.0 -0.2 -0.4 -0.3 -0.2 -0.2 -0.3 -0.3
  2013-2014 -0.4 -0.4 -0.3 -0.2 -0.2 -0.3 -0.4 -0.4 -0.2 0.1 0.3 0.2
WE 2014-2015 0.1 0.0 0.2 0.4 0.6 0.7 0.6 0.6 0.6 0.8 1.0 1.2
VSE 2015-2016 1.5 1.9 2.2 2.4 2.6 2.6 2.5 2.1 1.6 0.9 0.4 -0.1
WL 2016-2017 -0.4 -0.5 -0.6 -0.7 -0.7 -0.6 -0.3 -0.2 0.1 0.2 0.3 0.3
WL 2017-2018 0.1 -0.1 -0.4 -0.7 -0.8 -1.0 -0.9 -0.9 -0.7 -0.5 -0.2 0.0
WE 2018-2019 0.1 0.2 0.5 0.8 0.9 0.8 0.8 0.7 0.7 0.7 0.5 0.5
  2019-2020 0.3 0.1 0.2 0.4 0.5 0.6 0.5 0.5 0.4 0.2 -0.1 -0.3
ML 2020-2021 -0.4 -0.6 -0.9 -1.2 -1.3 -1.2 -1.1 -0.9 -0.8 -0.7 -0.5 -0.4
ML 2021-2022 -0.4 -0.5 -0.7 -0.8 -1.0 -1.0 -1.0 -0.9 -1.0 -1.1 -1.0 -0.9
WL 2022-2023 -0.8 -0.9 -1.0 -1.0 -0.9 -0.8 -0.7 -0.4 -0.2 0.1 0.5 0.8
ME 2023-2024 1.1 1.3 1.5                  
ENSO Type Season JJA JAS ASO SON OND NDJ DJF JFM FMA MAM AMJ MJJ
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