El Niño and La Niña Years and Intensities
Based on Relative Oceanic Niño Index (RONI)
Jan Null, CCM
Updated through February 2026
 
The Relative Oceanic Niño Index (RONI) is now 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) minus the overall average tropical 3-month sea surface temperature anomaly (SSTA).  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, an event is 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. [The legacy ONI page can be found here]
El Niño - 26 La Niña - 28
Weak - 10 Moderate - 7 Strong - 6 Very Strong - 3 Weak - 15 Moderate - 6 Strong - 7
1952-53 1951-52 1957-58 1982-83 1954-55 1949-50 1973-74
1953-54 1963-64 1965-66 1997-98 1964-65 1955-56 1975-76
1969-70 1968-69 1972-73 2015-16 1970-71 1995-96 1988-89
1976-77 1986-87 1987-88   1971-72 2011-12 1998-99
1977-78 1994-95 1991-92   1974-75 2020-21 1999-00
1979-80 2002-03 2023-24   1983-84 2021-22 2007-08
2004-05 2009-10     1984-85   2010-11
2006-07       2000-01    
2014-15       2005-06    
2018-19       2008-09    
        2016-17    
        2017-18    
        2022-23    
        2024-25    
        2025-26    

[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 RONI & ENSO Type
 https://www.cpc.ncep.noaa.gov/data/indices/RONI.ascii.txt
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
ML 1949-1950             -1.47 -1.27 -1.11 -1.09 -1.00 0.71
  1950-1951 -0.41 -0.24 -0.22 -0.29 -0.41 -0.56 -0.50 -0.17 0.25 0.60 0.64 0.69
ME 1951-1952 0.68 0.81 0.87 0.98 0.91 0.80 0.58 0.44 0.42 0.44 0.31 0.07
WE 1952-1953 -0.04 0.03 0.13 0.01 -0.01 0.20 0.53 0.76 0.77 0.83 0.84 0.79
WE 1953-1954 0.67 0.66 0.70 0.77 0.81 0.93 0.99 0.73 0.14 -0.20 -0.34 -0.26
WL 1954-1955 -0.49 -0.74 -0.85 -0.70 -0.56 -0.41 -0.38 -0.32 -0.35 -0.39 -0.37 -0.36
ML 1955-1956 -0.44 -0.61 -1.02 -1.43 -1.63 -1.27 -0.75 -0.32 -0.20 -0.06 -0.05 -0.08
  1956-1957 -0.28 -0.32 -0.31 -0.33 -0.37 -0.25 0.04 0.41 0.73 0.97 1.10 1.18
SE 1957-1958 1.23 1.26 1.23 1.31 1.52 1.87 2.02 1.88 1.40 1.07 0.83 0.68
  1958-1959 0.49 0.26 0.18 0.25 0.39 0.68 0.77 0.84 0.66 0.44 0.25 -0.06
  1959-1960 -0.23 -0.40 -0.29 -0.26 -0.11 -0.02 0.03 0.04 0.00 0.08 0.06 0.04
  1960-1961 0.11 0.17 0.17 0.07 0.01 0.02 0.05 0.06 0.03 0.10 0.26 0.34
  1961-1962 0.20 -0.09 -0.32 -0.31 -0.24 -0.12 -0.13 -0.09 -0.11 -0.22 -0.26 -0.21
  1962-1963 -0.11 -0.18 -0.25 -0.40 -0.46 -0.50 -0.38 -0.10 0.17 0.24 0.23 0.41
ME 1963-1964 0.73 0.99 1.04 1.10 1.22 1.25 1.13 0.68 0.10 -0.37 -0.63 -0.59
WL 1964-1965 -0.59 -0.62 -0.72 -0.76 -0.70 -0.51 -0.25 0.07 0.15 0.37 0.62 1.03
SE 1965-1966 1.38 1.67 1.94 2.03 2.04 1.90 1.65 1.52 1.26 0.87 0.46 0.29
  1966-1967 0.27 0.13 -0.02 -0.07 -0.12 -0.17 -0.17 -0.20 -0.39 -0.40 -0.19 0.18
  1967-1968 0.30 0.10 -0.02 -0.08 0.01 -0.02 -0.21 -0.33 -0.31 -0.19 0.16 0.45
ME 1968-1969 0.69 0.58 0.45 0.55 0.77 1.06 1.24 1.13 0.85 0.54 0.35 0.23
WE 1969-1970 0.23 0.43 0.72 0.78 0.74 0.57 0.51 0.31 0.25 0.11 0.01 -0.29
ENSO Type Season JJA JAS ASO SON OND NDJ DJF JFM FMA MAM AMJ MJJ
WL 1970-1971 -0.58 -0.69 -0.69 -0.63 -0.70 -0.91 -1.03 -1.02 -0.83 -0.60 -0.48 -0.41
  1971-1972 -0.44 -0.44 -0.47 -0.48 -0.52 -0.47 -0.31 0.02 0.41 0.77 0.94 1.12
SE 1972-1973 1.27 1.49 1.70 1.96 2.21 2.27 2.02 1.40 0.56 -0.25 -0.76 -1.06
SL 1973-1974 -1.24 -1.40 -1.54 -1.80 -1.95 -1.88 -1.54 -1.19 -0.95 -0.86 -0.79 -0.64
WL 1974-1975 -0.37 -0.19 -0.18 -0.36 -0.45 -0.25 -0.08 -0.13 -0.32 -0.47 -0.61 -0.78
SL 1975-1976 -0.91 -0.94 -1.05 -1.03 -1.08 -1.12 -1.03 -0.65 -0.30 -0.11 0.00 0.23
WE 1976-1977 0.46 0.67 0.94 1.10 1.13 1.13 1.01 0.93 0.52 0.31 0.19 0.35
WE 1977-1978 0.42 0.58 0.78 0.97 1.09 1.05 0.94 0.60 0.13 -0.18 -0.36 -0.29
  1978-1979 -0.32 -0.28 -0.20 -0.05 0.15 0.17 0.17 0.15 0.21 0.20 0.08 -0.08
WE 1979-1980 -0.02 0.20 0.39 0.49 0.54 0.66 0.64 0.47 0.27 0.21 0.31 0.33
  1980-1981 0.19 0.01 -0.04 0.06 0.20 0.17 0.01 -0.27 -0.34 -0.34 -0.26 -0.30
  1981-1982 -0.26 -0.18 -0.12 -0.16 -0.19 0.01 0.14 0.33 0.40 0.64 0.77 0.82
VSE 1982-1983 0.92 1.25 1.81 2.21 2.43 2.52 2.49 2.20 1.71 1.37 1.00 0.57
WL 1983-1984 0.10 -0.24 -0.59 -0.94 -1.14 -0.96 -0.54 -0.35 -0.35 -0.52 -0.57 -0.43
WL 1984-1985 -0.23 -0.07 -0.15 -0.51 -0.83 -1.00 -0.82 -0.60 -0.61 -0.69 -0.72 -0.54
  1985-1986 -0.36 -0.31 -0.22 -0.18 -0.09 -0.17 -0.34 -0.33 -0.21 -0.12 -0.10 -0.06
ME 1986-1987 0.26 0.58 0.91 1.15 1.36 1.49 1.56 1.48 1.26 0.97 0.89 1.05
SE 1987-1988 1.34 1.55 1.48 1.27 1.02 0.92 0.65 0.30 -0.21 -0.75 -1.37 -1.75
SL 1988-1989 -1.64 -1.32 -1.36 -1.63 -1.94 -1.92 -1.70 -1.42 -1.10 -0.85 -0.60 -0.43
  1989-1990 -0.35 -0.30 -0.24 -0.22 -0.15 0.03 0.24 0.29 0.27 0.25 0.21 0.22
ENSO Type Season JJA JAS ASO SON OND NDJ DJF JFM FMA MAM AMJ MJJ
  1990-1991 0.27 0.37 0.40 0.35 0.39 0.50 0.60 0.50 0.40 0.35 0.50 0.67
SE 1991-1992 0.81 0.80 0.91 1.17 1.70 2.08 2.32 2.24 2.04 1.73 1.35 0.90
  1992-1993 0.54 0.32 0.15 0.07 0.08 0.26 0.50 0.69 0.87 0.97 0.90 0.72
  1993-1994 0.49 0.51 0.46 0.36 0.28 0.27 0.32 0.33 0.43 0.54 0.64 0.64
ME 1994-1995 0.74 0.81 0.95 1.11 1.34 1.43 1.27 0.95 0.68 0.37 0.10 -0.13
ML 1995-1996 -0.32 -0.53 -0.74 -0.91 -0.95 -0.94 -0.87 -0.77 -0.62 -0.39 -0.30 -0.29
  1996-1997 -0.24 -0.24 -0.23 -0.27 -0.30 -0.29 -0.25 -0.10 0.17 0.52 0.95 1.34
VSE 1997-1998 1.69 2.01 2.25 2.38 2.36 2.34 2.16 1.82 1.25 0.77 0.14 -0.50
SL 1998-1999 -1.17 -1.41 -1.52 -1.52 -1.63 -1.65 -1.55 -1.28 -1.09 -1.00 -1.01 -0.99
SL 1999-2000 -0.99 -0.96 -0.97 -1.11 -1.38 -1.62 -1.67 -1.40 -1.09 -0.78 -0.63 -0.50
WL 2000-2001 -0.38 -0.37 -0.45 -0.58 -0.69 -0.68 -0.63 -0.55 -0.53 -0.46 -0.34 -0.13
  2001-2002 -0.01 0.00 -0.05 -0.17 -0.25 -0.27 -0.14 -0.03 0.01 0.11 0.37 0.66
ME 2002-2003 0.90 1.08 1.26 1.44 1.47 1.19 0.85 0.49 0.22 -0.23 -0.43 -0.29
  2003-2004 0.01 0.16 0.19 0.22 0.32 0.29 0.25 0.14 0.11 0.16 0.25 0.45
WE 2004-2005 0.66 0.82 0.86 0.77 0.73 0.67 0.55 0.43 0.31 0.31 0.20 0.03
WL 2005-2006 -0.10 -0.12 -0.02 -0.18 -0.50 -0.85 -0.93 -0.88 -0.65 -0.42 -0.14 -0.03
WE 2006-2007 0.11 0.31 0.54 0.75 0.94 0.92 0.60 0.16 -0.18 -0.36 -0.44 -0.53
SL 2007-2008 -0.59 -0.81 -1.05 -1.29 -1.41 -1.51 -1.60 -1.49 -1.26 -0.95 -0.76 -0.50
WL 2008-2009 -0.29 -0.21 -0.28 -0.40 -0.60 -0.79 -0.90 -0.85 -0.67 -0.42 -0.11 0.13
ME 2009-2010 0.25 0.39 0.56 0.94 1.34 1.56 1.45 1.11 0.64 0.05 -0.53 -0.99
ENSO Type Season JJA JAS ASO SON OND NDJ DJF JFM FMA MAM AMJ MJJ
SL 2010-2011 -1.28 -1.51 -1.68 -1.74 -1.72 -1.63 -1.43 -1.19 -0.92 -0.69 -0.48 -0.34
ML 2011-2012 -0.38 -0.51 -0.74 -0.94 -1.05 -0.99 -0.82 -0.65 -0.56 -0.47 -0.27 0.03
  2012-2013 0.34 0.43 0.40 0.23 -0.06 -0.38 -0.63 -0.60 -0.50 -0.43 -0.44 -0.43
  2013-2014 -0.38 -0.32 -0.28 -0.22 -0.22 -0.33 -0.49 -0.53 -0.33 -0.05 0.07 -0.01
WE 2014-2015 -0.13 -0.09 0.08 0.36 0.52 0.56 0.45 0.38 0.45 0.61 0.82 1.03
VSE 2015-2016 1.33 1.64 1.93 2.18 2.34 2.37 2.22 1.84 1.28 0.54 -0.06 -0.56
WL 2016-2017 -0.86 -1.00 -1.07 -1.11 -1.08 -0.99 -0.74 -0.54 -0.27 -0.09 0.05 0.05
WL 2017-2018 -0.17 -0.46 -0.73 -0.99 -1.15 -1.26 -1.12 -1.04 -0.88 -0.67 -0.31 -0.04
WE 2018-2019 0.05 0.16 0.40 0.65 0.77 0.67 0.62 0.62 0.60 0.52 0.34 0.21
  2019-2020 0.03 -0.10 -0.03 0.12 0.23 0.20 0.11 0.08 -0.03 -0.28 -0.56 -0.76
ML 2020-2021 -0.81 -0.93 -1.23 -1.47 -1.54 -1.37 -1.18 -1.04 -0.98 -0.79 -0.61 -0.52
ML 2021-2022 -0.59 -0.72 -0.92 -1.06 -1.23 -1.24 -1.22 -1.22 -1.28 -1.34 -1.22 -0.99
WL 2022-2023 -0.91 -1.01 -1.14 -1.12 -1.05 -0.97 -0.83 -0.62 -0.44 -0.21 0.07 0.37
SE 2023-2024 0.62 0.85 1.10 1.35 1.49 1.45 1.20 0.85 0.49 0.05 -0.26 -0.46
WL 2024-2025 -0.51 -0.64 -0.76 -0.82 -0.94 -1.08 -1.13 -0.90 -0.67 -0.52 -0.49 -0.43
WL 2025-2026 -0.47 -0.63 -0.77 -0.87 -0.93 -0.97 -0.95          
ENSO Type Season JJA JAS ASO SON OND NDJ DJF JFM FMA MAM AMJ MJJ
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