El Niño 2026–27 tracker
An El Niño is under way, and NOAA expects it to peak this coming winter. That matters for heat: El Niño is the single biggest natural driver of record global temperatures, and the hottest years on record have landed the year after it peaks. So a strong 2026–27 El Niño is an early warning that summer 2027 could break heat records — this page tracks it with the latest official NOAA numbers, updated monthly, and is honest about what it does and doesn’t tell you about your own weather.
In plain English: El Niño isn’t a season — it’s a warm-water pattern in the Pacific Ocean, like a fever that runs hottest in winter. Because the ocean takes months to heat the whole planet, its record-heat effect shows up the following year: a peak in winter 2026–27 is what raises the odds that summer 2027 runs hot, not the winter itself. (NOAA — the National Oceanic and Atmospheric Administration — is the official US science agency for this; its Climate Prediction Center, or CPC, is the primary source everyone else quotes.)
Data as of 2026-07-05. NOAA’s Climate Prediction Center issues its next ENSO discussion on 2026-07-09 — we refresh this page after each update. Source: CPC ENSO Diagnostic Discussion and the ONI data file.
January 2025 to now: 16 rolling ONI readings
The Oceanic Niño Index (ONI) is a three-month rolling average of the sea-surface temperature anomaly in the tropical Pacific. Anything at or above +0.5 °C (the dashed line) is officially El Niño; below −0.5 is La Niña. Read it left (oldest) to right (now), and watch the climb out of La Niña into a strengthening El Niño.
Chart data: NOAA CPC ONI file, pulled 2026-07-05. Values are °C anomaly, oldest (left) to newest (right). Orange bars above the centre line are El-Niño-leaning; blue bars below are La-Niña-leaning. The blue bars on the left are the past La Niña, not a forecast.
How strong is “strong”?
NOAA classifies El Niño by the peak ONI value it reaches. The current event has already crossed into El Niño territory; the open question is how high it climbs this winter.
| Category | Peak ONI (°C) | Where we are |
|---|---|---|
| Weak El Niño | 0.5 to <1.0 | ← current (AMJ 2026) |
| Moderate | 1.0 to <1.5 | — |
| Strong | 1.5 to <2.0 | — |
| Very strong | 2.0 and above | — |
Strength bands: NOAA CPC ONI strengths. A “very strong” event (peak ≥ 2.0 °C) would rank among the largest since records began in 1950.
What this means — and what it doesn’t
What El Niño reliably does: its clearest, most dependable effects in the United States are in winter, not summer — a jet stream shifted south and east tends to bring a wetter southern tier and Southeast and a milder north. NOAA’s own guidance notes El Niño’s US influence is “weak during the summer and more pronounced starting in the late fall through spring.”
What it does not do: El Niño does not cause your local summer heatwave. Any single heatwave, storm or flood has many causes, and — in NOAA’s words — a single El Niño “increases the odds” of certain patterns rather than guaranteeing them. Beware any tracker that tells you this summer will be hot “because of El Niño.” That’s not how the science reads.
Where El Niño does touch global heat is indirect and lagged: it nudges global average temperature up by roughly 0.07 °C for every 1 °C of Niño-3.4 warming, on a two-to-three-month delay. Because of that lag, the hottest calendar year on record has historically landed the year after a strong El Niño peaks — 1998, 2016 and 2024 all followed that pattern. 2024 was the warmest year since records began in 1850, at +1.29 °C above the 20th-century average.
Keep two signals separate, the way NOAA and the WMO do: the long-term warming trend from climate change is one thing; the year-to-year wobble from El Niño and La Niña is another. El Niño can amplify the impacts of a warming climate, but there’s no evidence it’s becoming more frequent or intense because of it.
Sources: NOAA Climate.gov ENSO blog and FAQ; NOAA NCEI 2024 global climate report; NWS El Niño explainer; World Meteorological Organization El Niño updates. Figures re-verified 2026-07-05.
What to actually do about it
Why this matters for heat: a peaking El Niño is the clearest early signal we get that the following summer carries elevated record-heat odds — so the sensible move is to be ready before demand and prices spike, not during a July heatwave. If a strong El Niño winter is coming, the useful response isn’t panic-buying an air conditioner today — it’s ordinary preparedness. If you’re in the wetter southern tier, that means drainage, sump pumps and storm supplies. Everywhere, it means knowing the heat-safety basics for the summer you’re actually in right now.
- How to stay safe in extreme heat — the heat-index bands, when a fan stops helping, and who’s most at risk. Includes a live heat-index checker.
- Cooling gear guides — if you do need to buy, the honest guides to portable ACs, window units and fans.