ENSO Monitor

Data through 19 Aug 2026 · baseline 1991-2020 · generated 26 Aug 2026 14:01 UTC

+2.6 °C
Niño 3.4 anomaly · latest week

▲El Niño Moderate · east-based El Niño Advisory

Official index (ONI, MJJ 2026): +1.39 °C, rising
Latest month ranks #1 of 45 Julys since 1981
Niño 1+2
+4.00°C
3rd of 45 Julys
Niño 3
+3.30°C
warmest of 45 Julys
Niño 3.4
+2.60°C
warmest of 45 Julys
Niño 4
+0.80°C
warmest of 45 Julys

Niño 3.4 monthly anomaly

1981-09 – 2026-07 · 539 months · anomalies against the 1991-2020 mean · dashed lines mark the ±0.5 °C event threshold

Designated El Niño Designated La Niña Shading marks NOAA's official episodes: ONI beyond ±0.5 °C for at least five consecutive overlapping 3-month seasons.
1985 1990 1995 2000 2005 2010 2015 2020 2025 -2 -1 0 +1 +2

Sea-surface temperature

· OISST v2.1 at 0.25° · 60°S–60°N (polar sea-ice margins excluded)

Departure from the 1991-2020 daily average for this date.

Niño 3.4 Niño 1+2
−40+4 °C

Daily Niño 3.4 anomaly by year

1981–2026 · shading is ±1/2/3σ across all years · hover any line for its year

2026 1981–2025 ±1σ ±2σ ±3σ
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec -4 -3 -2 -1 0 +1 +2 +3

Sources: NOAA CPC weekly Niño indices and ONI · NOAA OISST v2.1 (0.25°, global, 1981–present).
Niño indices computed from OISST on a single 1991-2020 baseline, so figures are internally consistent; CPC's own ONI uses shifting 30-year base periods and may differ by a few tenths.