ENSO Strengths

This table shows the forecast probability (%) of Niño-3.4 index exceeding a certain threshold (in degrees Celsius). For negative thresholds, the table shows the probability (%) of a Niño-3.4 index value that is less than (more negative) that value. For positive thresholds, the table shows the probability (%) of a Niño-3.4 index value that is greater than (more positive) that value. This tool supports the official ENSO Diagnostic discussion updated on the 2nd Thursday of each month.
Target	< -1.5°C	< -1.0°C	< -0.5°C	> 0.5°C	> 1.0°C	> 1.5°C
DJF	~0	60	~100	~0	~0	~0
JFM	~0	32	95	~0	~0	~0
FMA	~0	21	83	~0	~0	~0
MAM	~0	13	67	~0	~0	~0
AMJ	~0	9	48	1	~0	~0
MJJ	1	8	36	7	1	~0
JJA	1	8	30	14	3	~0
JAS	2	9	29	22	6	1
ASO	3	12	30	25	9	2
	< -1.5°C	< -1.0°C	< -0.5°C	> 0.5°C	> 1.0°C	> 1.5°C
The values are based on the analysis published in: L'Heureux, M. L., Tippett, Michael K., Takahashi, Ken, Barnston, Anthony G., Becker, Emily J., Bell, Gerald D., Di Liberto, Tom E., Gottschalck, Jon, Halpert, Michael S., Hu, Zeng-Zhen, Johnson, Nathaniel C., Xue, Yan, and Wang, Wanqiu, 2019: Strength Outlooks for the El Niño-Southern Oscillation. Wea. Forecasting, 34, 165-175, https://doi.org/10.1175/WAF-D-18-0126.1.