Relative Atlantic 3 Index (rATL3) by Month



International Desks
Climate Prediction Center
National Centers for Environmental Prediction


Notice: This page is updated automatically on the 5th day of each month. Because of the high frequency filter applied to the ERSSTv5 data (Huang et al. 2017, J.Climate), SST values may change up to two months after the initial "real time" value is posted. Therefore, the most recent index values should be considered an estimate.


DESCRIPTION: positve (red) and negitive (blue) periods based on a threshold of +/- 0.4oC , based on centered 30-year base periods updated every 10 years.


Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1950 0.22 0.05 0.0 0.06 0.46 0.04 -0.28 -0.7 -0.97 -0.94 -0.62 -0.92
1951 -0.54 -0.46 -0.65 -0.7 -0.37 0.13 0.46 0.46 0.42 0.1 0.11 0.4
1952 0.2 0.02 -0.19 0.01 -0.1 -0.25 -0.21 -0.42 -0.16 -0.27 -0.37 -0.61
1953 -0.55 -0.44 -0.35 -0.55 -0.36 -0.31 0.0 -0.14 -0.11 -0.3 -0.41 -0.45
1954 -0.51 -0.36 -0.48 -0.68 -0.89 -0.99 -1.29 -0.51 -0.23 0.36 0.21 0.17
1955 -0.25 -0.24 -0.38 -0.37 -0.38 -0.39 -0.57 -0.53 -0.08 -0.04 0.05 -0.42
1956 -0.65 -0.56 -0.61 -0.41 -0.45 -0.63 -0.79 -0.35 -0.18 -0.83 -0.82 -1.11
1957 -1.05 -0.74 -0.72 -0.33 -0.34 -0.15 -0.48 -0.4 -0.57 -0.72 -0.58 -0.41
1958 -0.65 -0.28 -0.56 -0.62 -1.88 -2.12 -1.46 -1.32 -1.13 -0.91 -1.01 -0.52
1959 -0.38 -0.01 0.19 0.31 0.11 0.04 -0.2 -0.3 -0.27 -0.28 -0.29 -0.14
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1960 -0.39 -0.38 -0.58 -0.33 -0.22 -0.25 0.08 0.11 -0.07 0.05 0.49 0.3
1961 0.26 0.09 0.07 0.16 0.7 0.0 -0.68 -0.49 -0.28 -0.03 0.13 -0.07
1962 0.05 -0.03 -0.22 -0.03 0.0 -0.03 -0.21 -0.17 -0.45 -0.02 -0.01 0.03
1963 0.07 0.11 0.19 0.25 0.7 1.28 1.45 1.21 0.79 0.57 0.39 0.48
1964 0.59 0.19 0.33 0.05 -0.41 -0.81 -0.43 -0.62 -0.92 -1.29 -1.09 -0.94
1965 -0.69 -0.6 -0.05 -0.07 -0.1 -0.54 -0.83 -0.59 -0.25 -0.72 -0.85 -0.78
1966 -0.34 -0.29 -0.4 -0.06 0.42 1.1 0.59 -0.27 -0.32 -0.22 0.02 0.36
1967 0.18 0.34 -0.35 0.17 -0.15 -1.04 -1.11 -0.7 -0.72 -1.06 -0.92 -0.75
1968 -0.5 -0.44 -0.4 -0.18 0.39 1.11 1.32 0.38 0.14 0.2 0.19 -0.03
1969 -0.17 0.01 -0.09 -0.0 -0.11 -0.5 -0.82 -0.82 -0.9 -0.68 -0.74 -0.49
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1970 -0.55 -0.26 -0.2 -0.31 -0.11 -0.43 -0.12 0.09 -0.09 -0.35 -0.22 -0.56
1971 -0.43 -0.36 -0.16 0.15 0.65 0.35 -0.33 -0.47 -0.32 -0.36 -0.9 -0.86
1972 -0.64 -0.33 -0.56 -0.33 -0.07 0.01 0.01 -0.46 -0.37 -0.2 0.1 0.32
1973 0.34 0.54 0.14 0.42 0.55 0.22 0.31 0.7 0.57 0.35 0.16 0.17
1974 0.12 0.06 0.29 0.44 0.77 0.98 0.73 0.32 -0.19 -0.45 -0.35 -0.55
1975 -0.45 -0.19 -0.23 -0.01 0.31 0.42 0.19 -0.34 -0.16 -0.09 0.05 -0.05
1976 -0.07 -0.26 -0.36 -0.66 -0.52 -0.61 -0.92 -0.54 -0.6 -0.72 -1.04 -0.83
1977 -0.87 -0.49 -0.63 -0.35 -0.39 -0.24 -0.36 -0.17 0.1 -0.35 -0.16 -0.14
1978 -0.38 -0.62 -0.92 -0.62 -0.64 -0.54 -0.23 -0.46 -0.5 -0.47 -0.51 -0.33
1979 -0.33 -0.39 -0.42 -0.18 -0.06 0.2 0.43 0.39 0.21 -0.05 0.2 -0.07
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1980 -0.38 -0.47 -0.73 -0.17 -0.06 -0.29 0.14 -0.19 0.06 -0.38 -0.25 -0.77
1981 -0.57 -0.28 -0.67 -0.46 -0.14 0.09 0.09 0.4 0.45 0.68 0.53 0.37
1982 0.21 0.29 0.24 -0.1 -0.13 -0.38 -0.62 -0.62 -0.44 -0.35 -0.73 -0.82
1983 -0.3 -0.12 -0.2 -0.45 -0.88 -0.78 -0.33 -0.18 -0.2 -0.42 -0.14 -0.22
1984 -0.16 0.25 0.45 0.14 0.29 0.6 0.62 0.9 0.91 0.37 0.43 0.26
1985 -0.0 0.19 -0.19 0.1 0.3 0.04 0.48 0.27 0.03 0.27 0.13 0.12
1986 -0.29 -0.1 -0.02 0.23 -0.04 0.6 0.08 -0.01 0.22 -0.47 -0.83 -0.39
1987 -0.53 -0.14 -0.03 0.07 0.07 0.59 1.18 0.74 0.62 0.13 0.37 0.2
1988 0.13 0.09 0.36 0.58 0.94 1.01 1.39 1.04 0.43 0.45 0.17 0.21
1989 -0.12 -0.05 -0.55 0.02 0.24 0.57 0.52 0.59 0.51 0.36 0.03 -0.48
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1990 -0.5 -0.37 -0.2 -0.05 -0.44 0.11 -0.21 -0.25 0.06 0.27 -0.15 -0.05
1991 -0.03 -0.35 -0.02 0.04 0.27 1.03 0.54 -0.01 -0.31 -0.35 -0.79 -0.8
1992 -0.48 -0.31 -0.18 -0.57 -1.05 -0.87 -0.49 -0.43 -0.31 -0.23 -0.48 -0.2
1993 -0.28 -0.49 -0.66 0.06 -0.09 -0.04 -0.0 -0.26 0.61 0.6 0.96 0.67
1994 0.28 -0.16 -0.05 0.37 0.13 -0.12 -0.56 0.01 -0.38 -0.15 0.15 0.16
1995 0.11 0.11 0.4 0.32 0.72 0.76 0.64 0.23 0.09 -0.27 0.15 -0.17
1996 -0.18 -0.21 0.04 0.36 0.75 1.21 0.72 0.25 -0.27 -0.22 -0.45 -0.6
1997 -0.66 -0.68 -0.76 -0.75 -0.45 -1.09 -0.43 -0.19 -0.34 0.14 0.05 0.35
1998 0.45 0.47 0.15 -0.07 -0.09 0.59 0.46 0.46 0.5 0.33 0.59 0.24
1999 0.01 -0.05 0.15 0.35 0.84 0.51 1.26 0.72 0.1 0.03 -0.07 0.28
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2000 -0.06 0.15 0.11 -0.07 0.17 -0.27 -0.33 -0.35 -0.35 -0.42 -0.46 -0.23
2001 -0.25 -0.13 0.18 0.2 0.15 -0.02 -0.25 -0.19 -0.01 0.0 -0.68 -1.04
2002 -0.72 -0.37 -0.36 -0.11 -0.01 0.26 0.17 0.16 -0.21 -0.22 -0.11 0.23
2003 0.17 0.26 0.39 0.04 -0.29 -0.08 0.5 0.4 0.34 0.01 0.19 0.48
2004 0.41 0.12 -0.08 -0.68 -0.49 -0.39 -0.18 0.06 0.25 -0.16 0.1 0.03
2005 0.11 0.13 0.06 -0.24 -1.01 -1.34 -0.88 -0.29 -0.04 0.2 0.08 0.08
2006 0.03 0.21 -0.03 -0.07 0.1 0.25 0.1 -0.29 -0.03 -0.14 -0.02 0.04
2007 -0.13 -0.06 -0.35 -0.23 0.24 0.34 0.36 0.18 0.55 0.26 0.2 0.36
2008 0.35 0.33 0.43 0.33 0.39 0.72 0.48 0.61 0.29 0.08 0.41 0.43
2009 0.3 0.24 0.46 0.24 0.68 -0.28 -0.56 -0.68 -0.43 -0.49 -0.54 -0.2
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2010 -0.04 0.21 0.12 0.17 0.27 0.55 0.14 0.29 0.43 0.63 0.64 0.37
2011 0.3 0.42 0.28 0.42 -0.07 -0.65 -0.45 -0.07 0.1 0.21 -0.05 -0.6
2012 -0.61 -0.66 -0.45 -0.59 -0.56 -0.42 -0.33 -0.31 -0.27 -0.09 -0.17 -0.14
2013 0.32 0.41 0.25 0.07 -0.46 -0.1 -0.47 -0.37 -0.53 -0.41 -0.46 -0.46
2014 -0.32 -0.17 -0.15 0.04 0.21 -0.19 -0.65 -0.52 -0.4 -0.23 -0.9 -0.68
2015 -0.21 -0.1 -0.11 -0.0 -0.03 -0.48 -0.51 -0.57 -0.46 -0.32 -0.01 -0.02
2016 -0.16 -0.39 -0.22 -0.1 -0.35 0.21 0.65 0.38 0.25 0.41 0.56 0.44
2017 0.02 0.01 0.01 0.16 0.01 0.02 -0.1 0.43 0.22 0.09 -0.17 -0.01
2018 0.16 0.03 -0.36 -0.18 0.15 0.4 0.51 0.51 0.48 0.34 0.47 0.32
2019 0.25 0.33 0.56 0.31 0.01 -0.17 -0.17 0.05 0.29 0.12 0.79 0.91
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2020 0.88 0.7 0.17 0.17 -0.15 -0.34 -0.14 -0.19 -0.13 0.23 -0.05 -0.28
2021 -0.2 -0.12 -0.31 -0.26 0.39 1.0 1.16 1.08 0.74 0.47 0.36 0.09
2022 0.02 -0.04 0.11 0.07 -0.11 0.25 -0.25 -0.12 0.02 0.04 -0.13 0.01
2023 0.35 0.24 -0.06 0.12 0.36 -0.29 -0.06 -0.09 -0.08 -0.14 0.21 0.6
2024 -0.1 0.38 0.93 0.66 -0.05 -0.53 -0.83 -0.27 -0.05 -0.01 -0.02 0.41
2025 0.21 0.31


Reference:
Tan, W., Y. Liu, X. Li, N. C. Johnson, and Z.-Z. Hu, 2023: Multi-Time Scale Variations in Atlantic Niño and a Relative Atlantic Niño Index. Geophys. Res. Lett., 50 (24), e2023GL106511. DOI: 10.1029/2023GL106511.

Data sources for indices:
ERSST.V5 : Huang, B., Peter W. Thorne, et. al, 2017: Extended Reconstructed Sea Surface Temperature version 5 (ERSSTv5), Upgrades, validations, and intercomparisons. J. Climate 
Climatology : 1991-2020


rATL3 regions :   [20ºW-0, 2.5ºS-2.5N]

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Questions or comments may be directed to Dr. Wassila Thiaw, Head, International Desks/NOAA, wassila.thiaw@noaa.gov with copy to zeng-zhen.hu@noaa.gov and li.xu@noaa,gov.