MEI Ranks (last update: 4 May 2012) 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 62-63 numbers in each column, the lowest number (1) would denote the strongest La Nina case for that bimonthly season, while the highest number (62 or 63) 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%ile) to define La Nina, near-normal, and El Nino, MEI ranks from 1-19 denote weak to strong La Nina conditions, while 44-62 (45-63) 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 51-62 (52-63) 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 57-62 (58-63) for El Nino. YEAR DECJAN JANFEB FEBMAR MARAPR APRMAY MAYJUN JUNJUL JULAUG AUGSEP SEPOCT OCTNOV NOVDEC 40 42 39 1969 47 51 46 53 49 48 39 34 32 42 44 40 1970 42 43 42 27 25 10 10 11 9 11 13 6 1971 5 3 1 1 2 4 6 8 6 6 6 13 1972 20 26 25 23 43 57 61 59 59 60 60 60 1973 60 59 52 48 26 9 11 7 4 4 4 1 1974 1 1 2 2 7 13 12 13 17 12 7 15 1975 21 21 14 12 10 6 2 3 2 1 2 3 1976 3 5 7 5 14 37 45 45 55 50 39 43 1977 44 38 37 50 38 44 51 47 52 52 51 49 1978 50 52 55 34 18 15 18 26 24 30 36 41 1979 46 41 32 38 40 39 37 44 48 44 46 52 1980 48 47 49 57 55 49 49 39 37 36 37 34 1981 32 33 45 54 33 30 31 31 34 34 32 31 1982 31 34 35 29 41 54 58 60 60 61 61 62 1983 63 63 63 63 62 61 59 56 40 32 29 30 1984 28 24 38 41 32 24 25.5 27 30 33 24 19 1985 22 22 15 21 11 26 27 21 20 28 33 27 1986 30 32 33 24 37 38 38 50 56 51 50 54.5 1987 57 56 60 60 59 60 60 61 61 59 56 57 1988 53 48 47 39 31 11 9 6 5 8 5 5 1989 7 6 13 14 13 20 17 15 25 25 31 35 1990 37 46 54 44 48 40 32 33 39 38 38 38 1991 40 39 44 47 50 56 55 55 45 53 55 59 1992 61 61 61 61 60 59 54 42 42 45 43 46 1993 49 55 56 59 58 58 56 54 54 55 48 44 1994 41 37 40 46 45 46 50 48 53 58 57 54.5 1995 56 54 53 45 44 41 34 25 23 20 20 22 1996 18 23 24 20 24 31 22 20 21 22 30 26 1997 25 20 26 49 57 62 62 62 62 62 62 61 1998 62 62 62 62 61 55 36 18 14 15 10 12 1999 8 9 12 10 12 17 16 12 12 13 14 8 2000 6 8 9 18 34 23 23 29 27 23 17 21 2001 23 16 20 26 35 28 35 40 28 26 28 33 2002 35 31 28 42 53 50 44 52 51 49 52 53 2003 55 53 51 40 29 32 33 36 41 43 41 37 2004 39 40 29 35 42 35 41 46 43.5 41 47 45 2005 38 49 57 52 51 43 43 38 36 27 23 20 2006 27 25 21 16 28 45 46 49 50 48 58 50 2007 52 45 34 28 36 18 20 17 10 10 9 9 2008 13 4 3 13 17 34 30 22 15 16 18 17 2009 16 15 17 25 39 52 52 53 46 54 53 51 2010 54 60 59 56 47 16 7 2 1 2 3 4 2011 2 2 4 4 19 22 28 16 13 14 16 14 2012 11 18 22 32 Next update: mid-June 2012 (this is in flux, hopefully sooner) Link to numerical MEI values is here. Go back to MEI homepage.