MEI Index (last update: 3 December 2014)

Bimonthly MEI values (in 1/1000 of standard deviations), starting with Dec1949/Jan1950, thru last
month.  More information on the MEI can be found on the MEI homepage.
Missing values are left blank.  Note that values can still change with each monthly update, even 
though such changes are typically smaller than +/-0.1.  All values are normalized for each bimonthly
season so that the 44 values from 1950 to 1993 have an average of zero and a standard deviation of "1".  
Responses to 'FAQs' can be found below this table:

YEAR    DECJAN  JANFEB  FEBMAR  MARAPR  APRMAY  MAYJUN  JUNJUL  JULAUG  AUGSEP  SEPOCT  OCTNOV  NOVDEC
1950	-1.018	-1.143	-1.29	-1.061	-1.416	-1.372	-1.332	-1.061	-.584	-.402	-1.157	-1.248
1951	-1.069	-1.193	-1.208	-.439	-.305	.438	.715	.847	.769	.743	.722	.466
1952	.408	.135	.086	.257	-.289	-.657	-.255	-.174	.357	.304	-.347	-.124
1953	.022	.382	.263	.711	.83	.227	.395	.248	.52	.091	.048	.314
1954	-.049	-.017	.178	-.51	-1.433	-1.585	-1.402	-1.467	-1.157	-1.374	-1.144	-1.107
1955	-.771	-.695	-1.134	-1.56	-1.631	-2.291	-1.953	-2.05	-1.831	-1.748	-1.834	-1.86
1956	-1.434	-1.297	-1.396	-1.158	-1.309	-1.513	-1.208	-1.134	-1.364	-1.464	-1.041	-1.013
1957	-.948	-.35	.156	.351	.901	.768	.924	1.122	1.179	1.097	1.129	1.231
1958	1.474	1.451	1.317	1.025	.724	.893	.711	.428	.178	.208	.486	.71
1959	.577	.804	.502	.218	.001	.01	-.187	.069	.055	-.082	-.18	-.265
1960	-.311	-.26	-.08	.017	-.334	-.247	-.361	-.254	-.476	-.364	-.338	-.432
1961	-.151	-.267	-.082	.017	-.289	-.098	-.175	-.242	-.268	-.513	-.435	-.645
1962	-1.093	-.99	-.715	-1.023	-.902	-.855	-.711	-.545	-.547	-.657	-.6	-.476
1963	-.701	-.838	-.696	-.814	-.477	-.052	.445	.626	.764	.832	.859	.749
1964	.856	.448	-.294	-.616	-1.275	-1.096	-1.411	-1.5	-1.291	-1.209	-1.202	-.902
1965	-.522	-.323	-.249	.102	.521	.944	1.391	1.477	1.405	1.22	1.367	1.258
1966	1.312	1.192	.697	.555	-.146	-.134	-.153	.165	-.091	-.015	.026	-.182
1967	-.473	-.94	-1.079	-1.066	-.469	-.315	-.606	-.427	-.634	-.679	-.421	-.366
1968	-.594	-.703	-.613	-.971	-1.097	-.748	-.55	-.121	.233	.425	.603	.359
1969	.689	.866	.445	.617	.697	.799	.426	.158	.161	.504	.653	.38
1970	.357	.405	.215	-.055	-.13	-.72	-1.137	-1.042	-1.245	-1.103	-1.09	-1.251
1971	-1.225	-1.521	-1.811	-1.896	-1.449	-1.485	-1.222	-1.234	-1.462	-1.421	-1.313	-1.005
1972	-.59	-.408	-.253	-.205	.478	1.166	1.896	1.823	1.512	1.626	1.722	1.746
1973	1.705	1.482	.841	.481	-.129	-.815	-1.072	-1.37	-1.743	-1.692	-1.519	-1.875
1974	-1.944	-1.794	-1.765	-1.682	-1.073	-.642	-.723	-.629	-.617	-1.05	-1.255	-.931
1975	-.565	-.606	-.882	-.969	-.852	-1.145	-1.477	-1.731	-1.874	-2	-1.793	-1.759
1976	-1.626	-1.399	-1.255	-1.191	-.477	.343	.617	.668	1.024	.947	.48	.554
1977	.517	.254	.091	.531	.331	.483	.859	.689	.812	1.006	.974	.878
1978	.779	.896	.955	.181	-.389	-.568	-.407	-.193	-.386	-.023	.197	.398
1979	.598	.361	-.011	.289	.384	.389	.355	.644	.769	.64	.737	1.015
1980	.694	.594	.669	.875	.922	.855	.782	.341	.284	.208	.238	.116
1981	-.248	-.165	.443	.638	.125	-.023	-.033	-.082	.179	.091	-.051	-.153
1982	-.284	-.15	.086	-.038	.407	.954	1.626	1.827	1.797	2.021	2.447	2.411
1983	2.689	2.909	3.038	2.873	2.561	2.18	1.738	1.137	.439	.003	-.171	-.177
1984	-.34	-.564	.131	.33	.144	-.107	-.129	-.185	-.084	.017	-.348	-.612
1985	-.561	-.603	-.737	-.483	-.716	-.09	-.146	-.398	-.537	-.139	-.053	-.293
1986	-.309	-.194	.033	-.166	.322	.316	.389	.811	1.157	.994	.867	1.183
1987	1.235	1.183	1.724	1.866	2.131	1.923	1.841	1.956	1.84	1.612	1.252	1.249
1988	1.089	.664	.456	.308	.103	-.682	-1.164	-1.378	-1.574	-1.342	-1.463	-1.344
1989	-1.167	-1.312	-1.056	-.84	-.459	-.256	-.448	-.494	-.28	-.312	-.061	.142
1990	.232	.529	.916	.397	.614	.43	.093	.126	.376	.247	.378	.334
1991	.308	.306	.393	.445	.718	1.14	1.009	1.01	.738	1.02	1.203	1.321
1992	1.751	1.872	1.992	2.271	2.141	1.74	.953	.536	.508	.672	.603	.645
1993	.7	.998	.979	1.39	1.992	1.499	1.096	1.006	.987	1.06	.826	.559
1994	.334	.191	.159	.426	.531	.764	.835	.742	.886	1.434	1.28	1.181
1995	1.197	.959	.862	.421	.508	.465	.178	-.198	-.456	-.478	-.486	-.561
1996	-.646	-.599	-.264	-.501	-.14	.022	-.21	-.399	-.495	-.381	-.155	-.341
1997	-.491	-.611	-.254	.497	1.121	2.314	2.764	3.004	3.005	2.363	2.527	2.316
1998	2.481	2.78	2.748	2.672	2.178	1.165	.284	-.417	-.655	-.844	-1.165	-1.015
1999	-1.152	-1.237	-1.068	-1.023	-.664	-.403	-.469	-.779	-.997	-1.007	-1.072	-1.208
2000	-1.198	-1.246	-1.138	-.521	.188	-.101	-.187	-.143	-.243	-.381	-.75	-.584
2001	-.542	-.718	-.607	-.145	.22	-.028	.267	.364	-.124	-.273	-.176	-.001
2002	-.053	-.213	-.201	.342	.801	.882	.613	.928	.813	.955	1.063	1.105
2003	1.18	.923	.82	.311	.07	.048	.093	.246	.442	.515	.528	.311
2004	.304	.327	-.125	.221	.495	.223	.478	.671	.526	.476	.795	.64
2005	.296	.795	1.018	.562	.782	.504	.492	.319	.262	-.164	-.4	-.588
2006	-.474	-.457	-.591	-.686	-.018	.565	.637	.76	.802	.899	1.299	.947
2007	.97	.509	.074	-.047	.213	-.3	-.294	-.448	-1.152	-1.133	-1.165	-1.172
2008	-1.012	-1.403	-1.635	-.942	-.348	.14	.011	-.262	-.631	-.77	-.605	-.67
2009	-.755	-.72	-.719	-.157	.375	.934	.949	.957	.77	1.025	1.066	1.003
2010	1.148	1.517	1.386	.867	.609	-.388	-1.17	-1.808	-2.019	-1.943	-1.588	-1.584
2011	-1.682	-1.565	-1.562	-1.488	-.281	-.136	-.076	-.462	-.753	-.956	-.965	-.985
2012	-1.049	-.705	-.417	.061	.73	.909	1.138	.575	.278	.112	.176	.031
2013	.038	-.165	-.171	.01	.108	-.242	-.436	-.586	-.175	.102	-.08	-.312
2014	-.318	-.269	-.017	.152	.932	.878	.816	.858	.5	.36	.712

(1) If you are trying to relate the MEI to monthly values of, say, precipitation, it may be 
    expedient to use the MEI value of month(i-1) and month(i) as if it were the value for 
    month(i) only. Since it takes a week or so for the global atmosphere to respond to tropical
    SST anomalies, the resulting lag is thus built into the analysis (I have verified this for
    southwest U.S. precipitation).

(2) Next update: 10 January 2015 (AMS Meeting, sorry!)

(3) Are there MEI values available prior to 1950? YES, the link to the sister website for
    the MEI.ext is here.
    Numerical values for the MEI.ext are available 
    here.

(4) Why do I believe that the MEI is better for monitoring ENSO than the SOI or various SST
    indices?  In brief, the MEI integrates more information than other indices, it reflects
    the nature of the coupled ocean-atmosphere system better than either component, and it is
    less vulnerable to occasional data glitches in the monthly update cycles. Now, if you are
    interested in ENSO impacts in a very specific part of the world, I would suggest that you
    obtain other ENSO indices as well and establish which one best fits your needs. 
    For instance, in Australia, Darwin sea level pressure and/or the SOI may be more appropriate
    than the MEI. My claim here is that the MEI does a better job than other indices for the 
    overall monitoring of the ENSO phenomenon, including, for instance, world-wide correlations 
    with surface temperatures and rainfall.

(5) I have been asked about MEI-like indices for the Indian Ocean, and at present I have no such
    project under way, nor do I know of any such data.

(6) Given the integrative approach of the MEI, I am very hesitant to give out subsets of the data
    that make up the MEI (for instance, its SST or SLP components alone).  Therefore, I will not
    honor requests of that nature.

(7) If you are interested in MEI predictions, please contact me directly under my e-mail address:
    Klaus Wolter (klaus.wolter@noaa.gov).

Link to ranked MEI values is here.

Go back to MEI homepage.