Peru & Ecuador coast
Flooding / extreme rain
Warm coastal waters drive torrential rain, flash floods and landslides. Historically the hardest-hit zone of any El Niño.
Guayaquil · Piura · Trujillo · Lima
Bulletin
Weekly bulletin
This week's Pacific numbers, in plain language.
What the equatorial Pacific did this week, in NOAA numbers and plain language, plus the regions most likely to feel it.
NOAA observation week:
Published by El Niño Observatory
Analysis generated:
This week's take
Pacific heated up. Weekly Niño 3.4 anomaly: +1.7 °C, +0.2 °C from last week. Ocean data, not a local weather warning.
Weekly Niño 3.4: +1.7 °CTraditional ONI: +0.46 °C · MAM 2026
The weekly Niño 3.4 temperature difference is +1.7 °C versus 1991–2020. This is a weekly ocean reading, not an official event-strength classification.
NOAA's current ENSO advisory and RONI
NOAA CPC adopted the relative index RONI in February 2026. Traditional ONI and weekly temperatures use different averaging methods; they are not interchangeable measures of event strength.
NOAA's current ENSO advisory and RONI ↗Niño 1+2
+3.1 °C
SST 26.2 °C
Niño 3
+1.9 °C
SST 28.5 °C
Niño 3.4
+1.7 °C
SST 29.4 °C
vs last week +1.5 °C
Niño 4
+1.3 °C
SST 30.2 °C
The ocean this week
For the week of 2026-06-17, Niño 3.4 stood at +1.7 °C (SST 29.4 °C). The change versus last week (+1.5 °C) was +0.2 °C. Niño 1+2 was +3.1 °C, Niño 3 +1.9 °C, and Niño 4 +1.3 °C. The 8-week trend is Warming.
What that means
Traditional three-month ONI: +0.46 (MAM 2026). El Niño's historical seasonal tendencies are not a forecast for your city. NOAA now uses RONI for official monitoring; these measurements are not interchangeable.
What to watch next
Follow the next NOAA ocean update and official ENSO advisory. For near-term hazards, use your national weather agency and local civil protection; weekly Pacific temperatures do not predict next week's local weather.
Regions most likely affected
Documented El Niño teleconnections, ranked from this week's NOAA readings. Not official warnings.
Amazon & Northeast Brazil
Drought / water / fire risk
Suppressed convection brings severe drought, record-low rivers, fires and crop failure across the Amazon basin and the semi-arid Northeast.
Manaus · Santarém · Belém · São Luís
Indonesia & Malaysia
Drought / water / fire risk
Severe drought dries peatlands, fuelling large-scale forest fires and transboundary haze; rice and palm yields fall.
Jakarta · Palembang · Pontianak · Surabaya
Southern Brazil, Uruguay & NE Argentina
Flooding / extreme rain
A strengthened subtropical jet brings persistent extreme rainfall. The 2023-24 Rio Grande do Sul floods are the canonical signature.
Porto Alegre · Pelotas · Santa Maria · Florianópolis
Eastern Australia
Extreme heat
Reduced rainfall and heatwaves raise bushfire danger and strain water supplies along the populous east coast.
Brisbane · Sydney · Canberra · Melbourne
Southern United States
Storms / coastal hazards
A stronger subtropical jet steers wetter, stormier winters across California and the Gulf Coast, with flood and severe-weather episodes.
Los Angeles · Houston · New Orleans · Tampa
Earlier weeks
Numbers: NOAA CPC weekly OISST and Oceanic Niño Index. Interpretation is independent.
Historical observations may be revised by NOAA. The seasonal index includes only seasons completed by this observation week; this is not a preserved original-release data vintage.