JMA El Nino outlook (Japan)

Forecasts and bulletins

JMA's Tokyo Climate Center publishes a monthly El Nino outlook. Its definition differs from NOAA's:

• Region: NINO.3 (5° N-5° S, 150° W-90° W).
• Rule: the 5-month running mean of the NINO.3 SST deviation stays at +0.5 °C or more for 6 consecutive months or longer.
• The deviation is measured from a sliding 30-year normal.

So JMA and NOAA can declare the start or end of an event a month or two apart. That is normal: they use different yardsticks.

Sources

• JMA Tokyo Climate Center -- El Nino monitoring and outlook
• JMA -- Monitoring and Prediction of El Nino (definition, PDF)

Related

• Nino 3
• NOAA ENSO Alert System (Watch, Advisory)
• Why numbers disagree between sources

ENSO status now

ONI (NOAA CPC)

+1.80 °C, JJA 2026 (previous +1.39 °C)

RONI (NOAA CPC)

+1.36 °C, JJA 2026

Nino 3.4 weekly (NOAA CPC / OISST)

+3.0 °C anomaly, week of 16 Sep 2026 (SST 29.6 °C)