East Asia
Japan El Niño 2026 outlook
Warmer than average
Seasonal outlook
October to December 2026
Likely warmer than usual
The European seasonal forecast model expects Japan to average about 1.6°C warmer than usual for this time of year.
Estimated chance of each outcome. With no forecast signal, each would be about 1 in 3.
Technical details
- Model: ECMWF SEAS5 (system 51) ensemble mean, from the Copernicus Climate Data Store.
- 2 m air temperature anomaly: +1.59°C, averaged over October to December 2026, relative to the model's 1993 to 2016 average.
- Taken at the model grid point nearest 36.20, 138.30, so it represents that area rather than the whole country.
- Chances (cooler / about usual / warmer): 21% / 21% / 58%. Estimated by Niño Tracker from the size of the anomaly, because the ensemble mean product does not include the model's own odds.
- Confidence is set by the anomaly's size: under 0.5°C low, 0.5 to 1°C moderate, 1°C or more high.
El Niño right now
Very strong El Niño
El Niño is a natural warming of the central and eastern tropical Pacific Ocean that shifts weather patterns around the world. Over July to September 2026, sea temperatures there averaged about 2.2°C above normal, which counts as a very strong event.
Technical details
- Oceanic Niño Index (ONI): +2.16 for JAS 2026. It is the 3-month average sea surface temperature anomaly in the Niño 3.4 region (5°N to 5°S, 120°W to 170°W), from NOAA.
- El Niño conditions are +0.5°C or more, La Niña −0.5°C or less, sustained for five overlapping 3-month seasons. Strength: weak 0.5 to 0.9, moderate 1.0 to 1.4, strong 1.5 to 1.9, very strong 2.0 or more.
- NOAA now uses a relative version of this index (RONI) for official monitoring. The ONI is still published each month.
- Last updated Oct 23, 2026, 12:00 AM UTC.
Upcoming 7 Days
Tokyo
- This week avg
- 16.2°
- Last year avg
- 14.3°
than the same week last year, on average.
Daily average
Temperatures in °C. Tap or hover the chart to compare each day.
Across these 8 cities, it averaged 15.0°, 2.3° cooler than this week's forecast of 17.3°.
Niño Tracker updates weather data two times a day.
El Niño and Japan: common questions
How will El Niño affect Japan in 2026?
The European seasonal forecast model expects Japan to average about 1.6°C warmer than usual for this time of year. The forecast covers October to December 2026. A strong signal. Outcomes usually follow it, but not always.
How does El Niño usually affect Japan?
Typical effects of past El Niño events in Japan: cooler summers, milder winters. Every event is different, so these are tendencies rather than guarantees.
How does La Niña affect Japan?
Typical effects of past La Niña events in Japan: warmer summers, colder winters. La Niña often pushes weather roughly the opposite way to El Niño.
What is the weather forecast for Japan this week?
Over the next 7 days, forecast lows and highs are: Tokyo 11 to 25°C, Osaka 10 to 26°C, Nagoya 7 to 24°C, Sapporo 2 to 15°C, Fukuoka 12 to 27°C, Sendai 6 to 19°C, Hiroshima 10 to 25°C and Naha 23 to 29°C. Across these cities the average is 17.3°C. Last year the same week averaged 15.0°C, so this week is forecast to be 2.3°C warmer.
Is El Niño happening right now?
El Niño is a natural warming of the central and eastern tropical Pacific Ocean that shifts weather patterns around the world. Over July to September 2026, sea temperatures there averaged about 2.2°C above normal, which counts as a very strong event. El Niño continues to strengthen, with a strong-to-very strong El Niño likely through January-March 2027 (remaining greater than an 83% chance).