MEI Index (last update: 10 March 2017)

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	-1.062	-1.163	-1.312	-1.104	-1.433	-1.391	-1.296	-1.053	-.634	-.433	-1.165	-1.261
1951	-1.07	-1.183	-1.222	-.523	-.36	.349	.666	.829	.743	.736	.703	.478
1952	.419	.117	.063	.22	-.309	-.723	-.316	-.378	.313	.275	-.349	-.124
1953	.03	.377	.256	.682	.784	.218	.368	.213	.501	.093	.075	.324
1954	-.051	-.048	.162	-.567	-1.416	-1.564	-1.378	-1.471	-1.166	-1.348	-1.14	-1.113
1955	-.762	-.697	-1.152	-1.634	-1.642	-2.243	-1.998	-2.073	-1.823	-1.753	-1.841	-1.877
1956	-1.437	-1.303	-1.413	-1.132	-1.317	-1.502	-1.259	-1.131	-1.359	-1.486	-1.038	-1.022
1957	-.941	-.372	.134	.353	.866	.769	.908	1.148	1.125	1.083	1.148	1.248
1958	1.472	1.439	1.32	1.013	.719	.864	.693	.427	.188	.213	.486	.671
1959	.548	.796	.496	.197	.013	-.018	-.134	.114	.105	-.06	-.17	-.261
1960	-.299	-.274	-.094	-.019	-.335	-.254	-.34	-.251	-.465	-.355	-.331	-.417
1961	-.163	-.257	-.097	0	-.288	-.137	-.216	-.304	-.301	-.539	-.436	-.634
1962	-1.087	-.988	-.724	-1.039	-.91	-.852	-.701	-.543	-.551	-.67	-.623	-.505
1963	-.739	-.863	-.69	-.792	-.477	-.087	.401	.597	.75	.814	.844	.744
1964	.874	.468	-.269	-.563	-1.242	-1.115	-1.405	-1.503	-1.311	-1.225	-1.239	-.936
1965	-.557	-.353	-.276	.053	.49	.915	1.36	1.443	1.406	1.219	1.362	1.252
1966	1.306	1.17	.678	.528	-.152	-.168	-.136	.155	-.085	-.044	.004	-.199
1967	-.473	-.919	-1.068	-1.059	-.455	-.266	-.521	-.395	-.621	-.683	-.426	-.378
1968	-.619	-.749	-.629	-.965	-1.095	-.771	-.527	-.102	.22	.435	.586	.347
1969	.664	.833	.452	.623	.696	.82	.467	.218	.177	.511	.666	.398
1970	.372	.415	.215	-.023	-.126	-.659	-1.089	-1.016	-1.252	-1.088	-1.084	-1.223
1971	-1.223	-1.528	-1.807	-1.888	-1.464	-1.448	-1.23	-1.225	-1.46	-1.421	-1.329	-.993
1972	-.596	-.424	-.262	-.196	.464	1.069	1.827	1.821	1.558	1.643	1.726	1.766
1973	1.726	1.5	.845	.481	-.106	-.769	-1.081	-1.347	-1.727	-1.667	-1.503	-1.848
1974	-1.939	-1.793	-1.76	-1.673	-1.077	-.67	-.769	-.671	-.627	-1.052	-1.251	-.905
1975	-.538	-.6	-.884	-.963	-.863	-1.15	-1.519	-1.73	-1.874	-1.987	-1.773	-1.757
1976	-1.61	-1.392	-1.246	-1.184	-.496	.307	.615	.664	1.038	.946	.493	.55
1977	.521	.273	.131	.539	.326	.451	.866	.695	.8	.986	.975	.86
1978	.773	.899	.936	.191	-.388	-.579	-.433	-.2	-.389	-.02	.186	.388
1979	.6	.362	-.015	.283	.38	.423	.369	.625	.786	.678	.746	.989
1980	.672	.585	.69	.907	.961	.907	.749	.336	.281	.201	.251	.089
1981	-.262	-.151	.457	.669	.161	-.019	-.048	-.088	.187	.112	-.038	-.141
1982	-.27	-.137	.106	-.009	.429	.944	1.604	1.799	1.811	2.024	2.428	2.411
1983	2.683	2.91	3.011	2.824	2.542	2.24	1.763	1.178	.497	.038	-.132	-.188
1984	-.33	-.529	.143	.347	.131	-.079	-.084	-.154	-.106	.001	-.352	-.603
1985	-.561	-.595	-.718	-.481	-.707	-.133	-.143	-.367	-.526	-.139	-.059	-.293
1986	-.301	-.195	.04	-.11	.35	.306	.383	.775	1.088	.979	.873	1.19
1987	1.25	1.205	1.719	1.866	2.14	1.964	1.859	1.999	1.894	1.647	1.271	1.282
1988	1.119	.706	.487	.353	.119	-.622	-1.145	-1.303	-1.506	-1.326	-1.468	-1.328
1989	-1.12	-1.262	-1.037	-.795	-.435	-.253	-.459	-.497	-.311	-.341	-.073	.115
1990	.237	.563	.945	.442	.637	.484	.12	.131	.378	.285	.389	.348
1991	.313	.314	.405	.463	.759	1.1	1.023	1.024	.76	1.009	1.189	1.32
1992	1.743	1.87	1.993	2.275	2.129	1.748	1.018	.57	.497	.641	.582	.648
1993	.687	.974	.99	1.409	1.998	1.591	1.17	1.042	.992	1.069	.834	.589
1994	.353	.182	.174	.465	.573	.788	.88	.773	.908	1.407	1.299	1.237
1995	1.22	.946	.879	.466	.563	.508	.207	-.143	-.426	-.477	-.478	-.554
1996	-.612	-.58	-.227	-.42	-.127	.068	-.204	-.374	-.437	-.349	-.146	-.336
1997	-.49	-.621	-.222	.535	1.165	2.292	2.805	3.04	3.044	2.401	2.542	2.335
1998	2.466	2.761	2.768	2.685	2.212	1.292	.347	-.331	-.6	-.798	-1.086	-.922
1999	-1.053	-1.14	-1.019	-.982	-.66	-.361	-.507	-.745	-.953	-.973	-1.05	-1.161
2000	-1.139	-1.21	-1.112	-.479	.169	-.053	-.184	-.145	-.227	-.387	-.714	-.566
2001	-.505	-.661	-.571	-.091	.233	.006	.27	.338	-.165	-.275	-.153	.019
2002	.009	-.171	-.137	.401	.851	.913	.685	1.017	.908	1	1.09	1.145
2003	1.218	.935	.831	.365	.111	.097	.144	.316	.477	.516	.57	.351
2004	.327	.359	-.056	.285	.539	.267	.541	.627	.572	.508	.805	.667
2005	.32	.81	1.055	.642	.836	.585	.49	.352	.315	-.167	-.392	-.57
2006	-.438	-.424	-.533	-.621	.008	.53	.691	.759	.823	.955	1.286	.951
2007	.985	.528	.112	.015	.247	-.215	-.288	-.441	-1.181	-1.217	-1.165	-1.193
2008	-1.02	-1.388	-1.583	-.874	-.368	.133	.054	-.266	-.551	-.692	-.597	-.663
2009	-.726	-.707	-.678	-.109	.361	.819	1.035	1.067	.735	.909	1.121	1.045
2010	1.067	1.52	1.427	.95	.643	-.325	-1.156	-1.683	-1.868	-1.899	-1.49	-1.577
2011	-1.739	-1.563	-1.511	-1.392	-.288	-.075	-.228	-.519	-.769	-.933	-.949	-.957
2012	-.993	-.695	-.377	.127	.747	.835	1.098	.619	.339	.081	.125	.094
2013	.096	-.08	-.128	.069	.146	-.168	-.355	-.48	-.133	.13	-.053	-.248
2014	-.275	-.266	.032	.248	.976	.98	.882	.954	.585	.438	.763	.558
2015	.42	.459	.67	.97	1.584	2.045	1.948	2.366	2.53	2.241	2.297	2.112
2016	2.227	2.169	1.96	2.07	1.699	1.001	.312	.175	-.101	-.379	-.212	-.121
2017	-.055	-.056

(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: 7 April 2017 (crossing fingers)  

(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.