CROPARC / CLIMATE REFERENCE

ENSO history: RONI chart & seasonal data

Inspect NOAA’s Relative Oceanic Niño Index (RONI) from 1950 through the latest included season, JAS 2026. Each observation covers three overlapping months, rather than a daily ocean temperature.

Included observations through 30 September 2026 · Anomalies in °C

Seasonal RONI history

Warm relative anomalies are brown; cool relative anomalies are blue. Colour saturates at ±3°C; printed values do not. A dash means no observation. This table does not assign official El Niño or La Niña episodes.

RONI (°C), baseline 1991–2020. DJF is assigned to its central January year; NDJ to its central December year.
Year	DJF	JFM	FMA	MAM	AMJ	MJJ	JJA	JAS	ASO	SON	OND	NDJ
2026	-0.91	-0.76	-0.44	-0.04	0.49	0.97	1.36	1.69	—	—	—	—
2025	-1.1	-0.85	-0.66	-0.5	-0.48	-0.36	-0.41	-0.59	-0.78	-0.93	-0.98	-1.04
2024	1.13	0.78	0.42	0.04	-0.28	-0.45	-0.49	-0.56	-0.67	-0.76	-0.88	-1.05
2023	-0.86	-0.68	-0.55	-0.31	-0.04	0.28	0.54	0.79	1.04	1.3	1.42	1.4
2022	-1.18	-1.13	-1.19	-1.26	-1.17	-0.95	-0.86	-0.94	-1.07	-1.1	-1.05	-0.99
2021	-1.32	-1.18	-1.08	-0.89	-0.68	-0.57	-0.6	-0.76	-0.95	-1.08	-1.24	-1.22
2020	0.14	0.1	0.02	-0.25	-0.55	-0.72	-0.76	-0.85	-1.16	-1.37	-1.46	-1.39
2019	0.68	0.64	0.57	0.53	0.37	0.24	0.04	-0.12	-0.01	0.15	0.29	0.22
2018	-1.08	-1.04	-0.9	-0.69	-0.33	-0.02	0.08	0.16	0.35	0.62	0.82	0.78
2017	-0.6	-0.44	-0.18	-0.1	-0.02	-0.04	-0.23	-0.46	-0.62	-0.82	-0.97	-1.14
2016	2.14	1.81	1.3	0.65	0.08	-0.43	-0.7	-0.81	-0.88	-0.96	-0.96	-0.89
2015	0.54	0.47	0.59	0.72	0.89	1.02	1.27	1.54	1.8	2.03	2.18	2.25
2014	-0.43	-0.38	-0.15	0.11	0.15	0	-0.14	-0.09	0.06	0.35	0.54	0.62
2013	-0.55	-0.57	-0.49	-0.44	-0.48	-0.48	-0.48	-0.38	-0.38	-0.22	-0.23	-0.27
2012	-0.77	-0.6	-0.5	-0.42	-0.26	0.01	0.33	0.43	0.37	0.21	-0.03	-0.27
2011	-1.42	-1.21	-0.97	-0.76	-0.52	-0.29	-0.29	-0.41	-0.7	-0.91	-1.02	-0.96
2010	1.44	1.11	0.69	0.1	-0.5	-0.97	-1.21	-1.39	-1.54	-1.61	-1.63	-1.55
2009	-0.96	-0.92	-0.7	-0.43	-0.05	0.24	0.35	0.42	0.53	0.86	1.29	1.5
2008	-1.73	-1.62	-1.39	-1.04	-0.8	-0.46	-0.24	-0.17	-0.26	-0.38	-0.6	-0.86
2007	0.6	0.16	-0.15	-0.33	-0.36	-0.44	-0.5	-0.79	-1.04	-1.33	-1.49	-1.65
2006	-0.9	-0.87	-0.69	-0.49	-0.19	-0.05	0.15	0.36	0.57	0.73	0.91	0.89
2005	0.54	0.4	0.26	0.25	0.2	0.05	-0.06	-0.11	-0.04	-0.18	-0.5	-0.81
2004	0.23	0.12	0.07	0.09	0.18	0.36	0.54	0.69	0.71	0.7	0.7	0.69
2003	0.85	0.47	0.23	-0.19	-0.34	-0.24	0.04	0.09	0.17	0.17	0.25	0.22
2002	-0.16	0.01	0.03	0.05	0.22	0.44	0.64	0.8	0.97	1.18	1.33	1.13
2001	-0.79	-0.62	-0.55	-0.41	-0.28	-0.08	0.01	-0.02	-0.05	-0.18	-0.27	-0.32
2000	-1.5	-1.31	-1.06	-0.88	-0.68	-0.54	-0.35	-0.29	-0.36	-0.55	-0.79	-0.82
1999	-1.56	-1.28	-0.99	-0.88	-0.81	-0.82	-0.83	-0.86	-0.87	-1.06	-1.33	-1.56
1998	2.13	1.82	1.22	0.81	0.07	-0.46	-1.05	-1.14	-1.24	-1.33	-1.51	-1.61
1997	-0.21	-0.03	0.17	0.47	0.83	1.2	1.5	1.84	2.07	2.22	2.25	2.28
1996	-0.87	-0.75	-0.58	-0.37	-0.25	-0.24	-0.2	-0.2	-0.2	-0.25	-0.3	-0.29
1995	1.17	0.86	0.55	0.2	-0.07	-0.23	-0.41	-0.57	-0.76	-0.93	-1.02	-0.99
1994	0.33	0.24	0.23	0.32	0.4	0.41	0.53	0.6	0.79	0.97	1.23	1.28
1993	0.55	0.7	0.86	1.06	1	0.77	0.45	0.46	0.48	0.46	0.44	0.42
1992	2.12	2.08	1.94	1.76	1.4	0.93	0.52	0.3	0.13	0.1	0.12	0.35
1991	0.57	0.53	0.42	0.42	0.56	0.7	0.86	0.83	1.01	1.2	1.66	1.97
1990	0.32	0.3	0.32	0.26	0.19	0.2	0.21	0.33	0.33	0.27	0.3	0.43
1989	-1.64	-1.37	-1.11	-0.89	-0.65	-0.43	-0.41	-0.38	-0.31	-0.23	-0.08	0.06
1988	0.45	0.11	-0.4	-0.91	-1.49	-1.74	-1.64	-1.36	-1.44	-1.71	-1.95	-1.94
1987	1.46	1.35	1.14	0.93	0.85	0.94	1.11	1.3	1.34	1.2	0.98	0.8
1986	-0.26	-0.27	-0.19	-0.14	-0.11	-0.01	0.26	0.57	0.79	1	1.22	1.42
1985	-0.83	-0.68	-0.75	-0.76	-0.77	-0.55	-0.33	-0.2	-0.16	-0.18	-0.14	-0.21
1984	-0.63	-0.52	-0.45	-0.59	-0.62	-0.51	-0.32	-0.17	-0.28	-0.61	-0.88	-0.93
1983	2.4	2.15	1.67	1.3	0.87	0.47	0.03	-0.23	-0.59	-0.9	-1.1	-0.96
1982	0.11	0.22	0.23	0.46	0.74	0.84	0.89	1.14	1.64	2.03	2.24	2.36
1981	-0.03	-0.18	-0.28	-0.24	-0.3	-0.26	-0.23	-0.16	-0.02	-0.17	-0.21	-0.08
1980	0.65	0.45	0.25	0.14	0.27	0.28	0.14	-0.1	-0.18	-0.06	0.14	0.09
1979	0.35	0.3	0.3	0.23	0.13	0.03	0.04	0.26	0.41	0.52	0.52	0.64
1978	0.96	0.71	0.26	-0.07	-0.33	-0.25	-0.32	-0.27	-0.27	-0.08	0.15	0.27
1977	0.96	0.89	0.46	0.32	0.25	0.51	0.48	0.48	0.62	0.89	1.1	1.05
1976	-1	-0.65	-0.26	-0.14	0.01	0.27	0.52	0.72	0.89	1.04	1.05	1.08
1975	-0.12	-0.13	-0.29	-0.42	-0.61	-0.73	-0.87	-0.88	-0.98	-0.95	-1.02	-1.11
1974	-1.6	-1.28	-0.97	-0.84	-0.57	-0.5	-0.27	-0.21	-0.24	-0.45	-0.59	-0.35
1973	1.69	1.25	0.58	-0.17	-0.73	-0.98	-1.1	-1.19	-1.3	-1.63	-1.86	-1.91
1972	-0.21	0.03	0.32	0.51	0.66	0.87	1.14	1.4	1.64	1.82	1.97	1.88
1971	-0.95	-1	-0.78	-0.57	-0.48	-0.37	-0.3	-0.25	-0.3	-0.4	-0.41	-0.38
1970	0.46	0.21	0.24	0.24	0.12	-0.23	-0.47	-0.64	-0.55	-0.57	-0.55	-0.85
1969	1.07	1	0.67	0.44	0.37	0.3	0.28	0.34	0.57	0.67	0.81	0.68
1968	-0.23	-0.36	-0.32	-0.26	0.07	0.32	0.56	0.46	0.39	0.56	0.74	1.02
1967	-0.26	-0.24	-0.35	-0.31	-0.09	0.21	0.25	-0.01	-0.11	-0.08	0.01	-0.03
1966	1.53	1.29	1.04	0.59	0.31	0.22	0.32	0.19	0	-0.03	-0.12	-0.22
1965	-0.16	0.1	0.22	0.36	0.64	1.01	1.33	1.49	1.76	1.86	1.99	1.81
1964	1	0.6	0.1	-0.37	-0.66	-0.66	-0.59	-0.55	-0.53	-0.64	-0.58	-0.48
1963	-0.29	-0.12	0.04	0.06	0.01	0.37	0.73	1.08	1.07	1.06	1.11	1.07
1962	-0.01	-0.01	0	-0.16	-0.17	-0.14	0.01	-0.1	-0.15	-0.3	-0.29	-0.37
1961	0.03	0.08	0.03	0.06	0.24	0.3	0.2	-0.07	-0.23	-0.16	-0.06	0.02
1960	0.2	0.19	0.21	0.25	0.16	0.06	0.12	0.2	0.26	0.08	-0.07	-0.09
1959	0.77	0.83	0.64	0.48	0.33	0.09	-0.11	-0.23	-0.07	0.04	0.24	0.22
1958	1.89	1.79	1.31	0.95	0.66	0.56	0.45	0.26	0.23	0.24	0.36	0.64
1957	0	0.22	0.53	0.83	0.88	0.9	1.03	1.05	1.14	1.16	1.45	1.75
1956	-0.81	-0.4	-0.12	-0.09	-0.03	-0.01	-0.15	-0.18	-0.12	-0.14	-0.14	-0.17
1955	-0.12	-0.14	-0.13	-0.38	-0.36	-0.52	-0.4	-0.7	-0.9	-1.31	-1.4	-1.31
1954	0.63	0.63	0.31	-0.02	-0.24	-0.21	-0.45	-0.62	-0.54	-0.31	-0.09	-0.18
1953	0.4	0.67	0.68	0.72	0.94	0.84	0.68	0.73	0.65	0.84	0.57	0.66
1952	0.65	0.33	0.46	0.24	-0.03	-0.45	-0.41	-0.14	0.08	0.04	-0.1	0.1
1951	-0.28	0.09	0.48	0.63	0.59	0.69	0.79	0.97	1.04	0.98	0.94	0.71
1950	-1.19	-1.08	-0.96	-1	-0.99	-0.75	-0.38	-0.32	-0.29	-0.38	-0.36	-0.5

RONI is not ONI

RONI expresses Niño 3.4 sea-surface temperature anomalies relative to the tropical ocean background. ONI is a different index; the two histories should not be spliced together. The values here retain NOAA’s RONI definition and 1991–2020 baseline.

Read NOAA’s RONI definition ↗

Inspect this edition in the dashboard ↗

NOAA sources & dates

This page contains a dated prepared edition. The dashboard can contain newer evidence; source collection and observation periods are different clocks.

RONI seasonal observations · retrieved 4 October 2026 · published 3 October 2026
Official ENSO discussion · retrieved 2 October 2026
Official ENSO probabilities · retrieved 2 October 2026

Attribution & exact climate edition

NOAA Climate Prediction Center; CropArc normalized presentation. NOAA/NWS public domain; attribution; no endorsement.

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