MEI Ranks (last update: 4 November 2009) Bimonthly ranks of the MEI, since the beginning of record in Dec1949/Jan1950. If two MEI values are identical within the same bimonthly season, their rank is split between them, leading to a ".5" value. Missing values are left blank. How can one interpret these ranks? Given that there are 59 or 60 numbers in each column, the lowest number (1) would denote the strongest La Nina case for that bimonthly season, while the highest number (59 or 60) would indicate the strongest El Nino case. For instance, in December-January (DECJAN), the strongest La Nina was recorded in 1974, while the strongest El Nino occurred in 1983. If we use percentiles (say, 30%-tile) to define La Nina, near-normal, and El Nino, MEI ranks from 1-18 denote weak to strong La Nina conditions, while 43-60 (or 42-59) denote weak to strong El Nino conditions. If one uses the quintile definition for (moderate or stronger) ENSO events, MEI ranks from 1-12 would denote La Nina, while 49-60 (48-59) would denote El Nino. Finally, the comparison figures on this website refer to strong ENSO events, such as might be defined by the top 6 (one tenth or smaller) ranks, such as 1-6 for La Nina, and 55-60 (54-59) for El Nino. YEAR DECJAN JANFEB FEBMAR MARAPR APRMAY MAYJUN JUNJUL JULAUG AUGSEP SEPOCT OCTNOV NOVDEC 1950 9 9 5 6 4 5 5 9 14 19 8 5 1951 8 7 7 20 22 37 46 49 50 44 43 40 1952 41 34 33 34 20 12 19 23 36 37 23 30 1953 34 41 41 53 51 33.5 38 34 41 32 33 34 1954 32 33 35 17 2 2 4 4 9 6 11 9 1955 13 16 8 2 1 1 1 1 2 2 1 1 1956 3 5 4 5 5 3 6 8 6 4 13 11 1957 11 24 37 43 52 45 51 54 55 54 51 52 1958 56 56 56 55 50 50 45 39 33 34 38 45 1959 43 48 46 33 29 30 24 29 29 27 26 26 1960 28 27 28 28 19 21 18 19 19 21 22 22 1961 31 28 29 30 21 25 20 18 23 17 21 15 1962 7 11 14 7 9 8 12 13 18 16 16 20 1963 14 13 17 13 15 26 34 41 45 45 48 46 1964 49 42 21 15 6 7 3 3 7 8 6 13 1965 20 26 23 31 43 51 55 56 56 55 56 55 1966 55 55 47 46 25 22 26 32 27 28 32 28 1967 23 12 9 8 16 17.5 13 14 12 15 19 23 1968 16 14 18 11 7 10 14 27 32 38 41 38 1969 47 49 43 51 49 46 40 33 31 39 42 37 1970 39 40 40 26 24 11 9 10 8 10 12 6 1971 4 2 1 1 3 4 7 7 5 5 5 10 1972 19 25 24 24 44 55 58 58 57 58 57 57 1973 58 57 51 48 26 9 10 5 3 3 4 2 1974 1 1 2 3 8 14 11 12 13 11 7 14 1975 22 20 13 9 10 6 2 2 1 1 2 3 1976 2 3 6 4 13 35 43 45 53 47 37 41 1977 42 36 38 50 38 42 48 46 49 49.5 50 47 1978 48 51 55 32 18 15 17 20 20 29 34 39 1979 44 39 30 37 39 39 36 43 47 43 44 49 1980 46 45 48 54 54 49 47 37 35 35 35 32 1981 29.5 29 44 52 31 28 28 28 30 33 31 29 1982 29.5 31.5 32 27 41 52 56 57 58 59 59 59 1983 60 60 60 60 60 59 57 55 40 31 27 27 1984 26 21 39 42 33 23 27 22 28 30 24 18 1985 18 19 16 19 11 24 23 16 16.5 26 30 25 1986 27 30 31 25 36 36 35 47 54 49.5 47 53 1987 54 54 57 57 59 58 59 59 59 57 53 56 1988 51 46 45 36 32 13 8 6 4 7 3 4 1989 6 6 11 14 14 19 16 15 24 24 29 33 1990 35 44 52 44 45 38 31 31 37 36 36 36 1991 37 37 42 39 47 53 53 52 44 51 52 54 1992 57 58 58 58 58 57 52 40 39 42 39 43 1993 45 53 54 56 57 56 54 53 52 53 46 42 1994 40 35 36 45 46 44 49 44 43 56 54 51 1995 52 50 50 38 42 41 33 30 21 18 18 21 1996 17 18 22 18 23 27 25 21 22 20 28 24 1997 24 22 25 47 55 60 60 60 60 60 58 58 1998 59 59 59 59 56 54 37 25 15 13 10 12 1999 10 10 12 10 12 16 15 11 11 12 14 7 2000 5 8 10 21 28 20 22 26 25 23 15 16 2001 21 17 20 23 34 29 32 36 26 22 25 31 2002 33 31.5 26 41 53 47 42 50 48 46 49 50 2003 53 52 49 40 30 31 29 35 38 41 40 35 2004 38 38 27 35 40 33.5 41 42 42 40 45 44 2005 36 47 53 49 48 40 39 38 34 25 20 19 2006 25 23 19 16 27 43 44 48 51 52 55 48 2007 50 43 34 29 35 17.5 21 17 10 9 9 8 2008 12 4 3 12 17 32 30 24 16.5 14 17 17 2009 15 15 15 22 37 48 50 51 46 48 # # Next update: 5 December 2009 (possibly earlier) Link to numerical MEI values is here. Go back to MEI homepage.