El Nino Watch

El Nino 2026-27 Live Tracker: ONI, Nino 3.4, Forecasts

Live El Nino 2026-27 tracker: NOAA ONI and RONI, weekly Nino 3.4 anomaly, IRI and CPC forecasts, a hazards map and a Koh Samui (Thailand) risk watch.

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)
NOAA CPC ENSO status
El Niño Advisory (issued 10 Sep 2026), El Niño is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27. source
IRI ENSO probabilities (issued 21 Sep 2026)
SON: El Nino 100%, neutral 0%, La Nina 0%; OND: El Nino 100%, neutral 0%, La Nina 0%; NDJ: El Nino 100%, neutral 0%, La Nina 0%; DJF: El Nino 100%, neutral 0%, La Nina 0%
Koh Samui watch level
Prepare (evaluated 25 Sep 2026 13:32 UTC)
Data updated
25 Sep 2026 13:32 UTC

Briefing (25 Sep 2026 10:21 UTC)

Strong El Nino (ONI +1.80 °C, JJA 2026; RONI +1.36 °C; Nino 3.4 +3.0 °C week of 16 Sep); NOAA CPC: El Niño Advisory (10 Sep). Maenam, Koh Samui: PREPARE. No immediate threat on Samui: rain 108% of normal (90 d to 19 Sep), waves max 0.5 m (forecast to Sun 27 Sep), no cyclone within 800 km (nearest 1,997 km). Watch: heavy rain / flood -- TMD heavy-rain bulletin 225/2569 for the South, in force to Sun 27 Sep (forecast 24 mm over 3 days). Next risk: NE-monsoon heavy rain and rough seas Oct-Dec 2026 (November wettest); water stress Feb-Apr 2027.

ENSO state

  • NOAA CPC status (bulletin): El Niño Advisory (issued Thu 10 Sep 2026; next update Thu 8 Oct 2026).
  • RONI (NOAA's official index since 2026, observed): +1.36 °C for JJA 2026 (1 Jun-31 Aug) = moderate El Nino range.
  • ONI (3-month index, observed): +1.80 °C for JJA 2026 (1 Jun-31 Aug) = strong El Nino.
  • Nino 3.4 weekly SST anomaly (NOAA CPC OISST, observed): +3.0 °C for the week 13-19 Sep 2026 (centred on Wed 16 Sep, UTC).
  • Nino 3.4 daily SST anomaly (OISST via Climate Reanalyzer, preliminary): +2.92 °C on Wed 23 Sep 2026.
  • Southern Oscillation Index (observed): NOAA CPC standardized -1.1 for Aug 2026; BoM (Troup) -14.6 for Aug 2026. Sustained negative values (BoM below -7) = El Nino-like atmosphere.
  • MEI.v2 (NOAA PSL, observed): +2.54 for JA 2026.
  • JMA (Wed 9 Sep 2026): El Niño conditions are considered to have persisted in the equatorial Pacific since Spring 2026. They are virtually certain (100%) to continue until boreal winter.

Forecast

  • IRI model-based forecast (issued Mon 21 Sep 2026), El Nino probability by 3-month season: SON 100%, OND 100%, NDJ 100%, DJF 100%, JFM 100%, FMA 100%.
  • Last season shown (MJJ): El Nino 55%, neutral 42%, La Nina 3%.
  • NOAA CPC synopsis (Thu 10 Sep 2026): El Niño is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27.

Maenam, Koh Samui

  • Level: PREPARE (evaluated 25 Sep 17:21 ICT). Prepare -- strong El Nino (ONI +1.80 °C JJA 2026; RONI +1.36 °C; Nino 3.4 +3.0 °C week of 16 Sep). No immediate threat on Samui: rain 108% of normal (90 d to 19 Sep), waves max 0.5 m (forecast to Sun 27 Sep), no cyclone within 800 km (nearest 1,997 km). Watch: heavy rain / flood -- TMD heavy-rain bulletin 225/2569 for the South, in force to Sun 27 Sep (forecast 24 mm over 3 days). Next risk: NE-monsoon heavy rain and rough seas Oct-Dec 2026 (November wettest); water stress Feb-Apr 2027.
  • El Nino (event strength): PREPARE -- +3.0 °C (Nino 3.4, week of 16 Sep) [observed, valid for 2026-09-13/2026-09-19].
  • Heavy rain / flooding: VIGILANCE -- 16 mm on Sat 26 Sep (forecast wettest day; 24 mm over 3 days) [forecast, valid for 2026-09-26].
  • Media / social signal (Samui, Thailand): VIGILANCE -- 2 Samui items in 14 days [observed, valid for 2026-09-12/2026-09-25].
  • Rain deficit / water shortage: NORMAL -- 108% of normal (22 Jun-19 Sep: 303 mm vs 282 mm normal) [ERA5 reanalysis, valid for 2026-06-22/2026-09-19].
  • Extreme heat: NORMAL -- 37.5 °C feels-like, forecast for Wed 30 Sep [forecast, valid for 2026-09-30].
  • Tropical cyclone / wind: NORMAL -- 61 km/h max gust, forecast for Sun 27 Sep; no cyclone within 800 km [forecast, valid for 2026-09-27].
  • Sea state (ferries, isolation): NORMAL -- 0.5 m, forecast max on Sun 27 Sep [forecast, valid for 2026-09-27].
  • Air quality (PM2.5, haze): NORMAL -- 6.9 µg/m³ PM2.5 (observed, at Environment Agency Section 14, Surat Thani) [observed, valid for 2026-09-25T08:00:00+00:00].
  • Marine heat / coral bleaching: NORMAL -- 0.0 °C-weeks (West Gulf of Thailand, 23 Sep) [observed, valid for 2026-09-23].
  • Action (prepare): Build 14 days of self-sufficiency: water, no-cook food, medication (30 days).
  • Action (prepare): Fill and clean the cistern; fit a filter and keep purification tablets.
  • Action (prepare): Charge power banks, headlamps, batteries; test the generator/solar panel.

Hazards

  • Within 800 km: flood -- Flood in Malaysia (green, 556 km away, updated 2026-09-22 UTC).
  • Within 800 km: flood -- Flood in Thailand (green, 682 km away, updated 2026-09-25 UTC).
  • Within 800 km: bleaching -- Western Gulf of Thailand: Bleaching Watch (DHW 0.0) (info, 150 km away, updated 2026-09-23 UTC).
  • Within 800 km: bleaching -- Southwestern Thailand: Bleaching Watch (DHW 0.0) (info, 244 km away, updated 2026-09-23 UTC).
  • Within 800 km: 2 minor fire cluster(s) (green, NASA FIRMS satellite detections), nearest 446 km.
  • Worldwide: 3 GDACS orange/red alerts, 0 red.
  • ORANGE cyclone: Tropical Cyclone ONE-26 (1,997 km away, updated 2026-09-25 UTC).
  • ORANGE cyclone: Tropical Cyclone POLO-26 (15,773 km away, updated 2026-09-25 UTC).
  • ORANGE flood: Flood in India (2,560 km away, updated 2026-09-22 UTC).

Latest official bulletins

  • 2026-09-25: JTWC Significant Tropical Weather Advisory For The Western And South Pacific Oceans/250600Z-260600Zsep2026
  • 2026-09-25: Heavy to Very Heavy Rain in Thailand No.8 (224/2026)
  • 2026-09-24: JTWC Significant Tropical Weather Advisory For The Western And South Pacific Oceans/240600Z-250600Zsep2026
  • 2026-09-24: Heavy to Very Heavy Rain in Thailand No.7 (223/2026)
  • 2026-09-24: Heavy to Very Heavy Rain in Thailand No.6 (222/2026)

Data gaps

  • 79 of 85 sources fresh and OK.
  • STALE: climate.gov ENSO blog -- newest data 2025-06-12 (allowed age 45 d).
  • Failing on last run: gdelt_news.
  • Not configured (optional credentials): bluesky_search, reliefweb_reports, webcams_windy.

Koh Samui, Thailand

Prepare -- strong El Nino (ONI +1.80 °C JJA 2026; RONI +1.36 °C; Nino 3.4 +3.0 °C week of 16 Sep). No immediate threat on Samui: rain 108% of normal (90 d to 19 Sep), waves max 0.6 m (forecast to Sun 27 Sep), no cyclone within 800 km (nearest 1,997 km). Watch: heavy rain / flood -- TMD heavy-rain bulletin 225/2569 for the South, in force to Sun 27 Sep (forecast 25 mm over 3 days). Next risk: NE-monsoon heavy rain and rough seas Oct-Dec 2026 (November wettest); water stress Feb-Apr 2027.

Full Koh Samui risk watch