Weekly update · October 28, 2026
El Niño Update, Week of October 28, 2026: Niño 3.4 at +3.4 °C
In the week of October 28, 2026, the sea surface temperature anomaly in the Niño 3.4 region — NOAA's main El Niño indicator — was +3.4 °C (30.2 °C actual), which corresponds to El Niño conditions.
Compared with the previous week it held steady, and over the last four weeks it rose 0.2 °C.
Off the coast of Peru and Ecuador (Niño 1+2) the anomaly was +5.4 °C (it rose 0.2 °C); this coastal warming is what most affects rain on the South American Pacific coast.
One year earlier, Niño 3.4 was at -0.6 °C.
The ongoing event, El Niño 2026, has reached a 3-month ONI of +2.5 °C, ranking 2nd since 1950.
| Region | Area | Anomaly | vs. last week |
|---|---|---|---|
| Niño 1+2 | coast of Peru and Ecuador | +5.4 °C | +0.20 |
| Niño 3 | eastern Pacific | +4.4 °C | +0.10 |
| Niño 3.4 | central Pacific (official index) | +3.4 °C | 0.00 |
| Niño 4 | western-central Pacific | +1.4 °C | +0.30 |
Niño 3.4, previous 52 weeks
Cities far from normal that week
- Guayaquil: 430 mm of rain in 30 days (75× normal)
- Santiago: 205 mm of rain in 30 days (18× normal)
- Piura: 58 mm of rain in 30 days (14× normal)
- Trujillo: +7.6 °C above normal in 30 days
- Cali: +7.2 °C above normal in 30 days
- Monterrey: +5.9 °C above normal in 30 days
- Houston: only 6% of normal rain in 30 days
- Seattle: only 14% of normal rain in 30 days
Active disaster alerts
- Tropical Cyclone MURASU-26 (India) · red
GDACS (ONU / Comisión Europea).
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Frequently asked questions
Was there an El Niño in the week of October 28, 2026?
The weekly Niño 3.4 anomaly was +3.4 °C, above the +0.5 °C El Niño threshold. NOAA declares an event using the 3-month ONI and the atmospheric response.
Where do these numbers come from?
From NOAA's Climate Prediction Center weekly OISST v2.1 sea surface temperature data, published every Monday.
Source: NOAA CPC weekly OISST v2.1 (public domain). Generated automatically by El Niño Forecast; free to cite with a link.