El Niño 2026–27 in Tonga
Odds favour a drier-than-normal December–February in Tonga (90% chance). That matches the past: 13 of 15 El Niño seasons since 1980 were drier than usual here.
Temperatures: likely warmer than the 1993–2016 average (51% chance).
El Niño status: El Niño Advisory (NOAA, 12 November 2026). Outlook: Copernicus, issued November 2026.
Outlook for the next six months
December–February
Rainfall: likely drier
Temperature: likely warmer
February–April
Rainfall: likely drier
Temperature: likely warmer
In the tropics, seasonal forecasts generally have useful skill during strong El Niño years, but they give odds, not certainties. “Normal” means the middle third of the model's own 1993–2016 range; because the climate has warmed since then, “warmer” is the usual result almost everywhere.
Source: Copernicus Climate Change Service seasonal forecast (Copernicus Climate Change Service (C3S) seasonal forecasts, ECMWF system 51), country average. How this is calculated.
Air quality, next 4 days
Worst forecast day: Nuku'alofa, 17 November 2026: Moderate (PM2.5 12.4 µg/m³, AQI 57).
| City | 11/15 | 11/16 | 11/17 | 11/18 |
|---|---|---|---|---|
| Nuku'alofa (capital) | 54Moderate | 54Moderate | 57Moderate | 35Good |
| Neiafu | 56Moderate | 53Moderate | 56Moderate | 49Good |
AQI = US EPA 24-hour PM2.5 scale (2024). Model forecast for an area of about 40 km, not a local measurement. Local levels can be higher or lower. Dates are UTC days.
Source: Copernicus Atmosphere Monitoring Service global forecast, run 2026-11-14 00 UTC.
What happened in past El Niños
Each row compares El Niño seasons with all other years in 1979-2025, after removing the long-term trend.
| Season | Rainfall | Temperature |
|---|---|---|
| Dec–Feb | Drier in 13 of 15 El Niño seasons (about 42% less rain on average) | No consistent pattern (−0.3 °C on average) |
| Jan–Mar | Drier in 11 of 13 El Niño seasons (about 35% less rain on average) | Cooler in 10 of 13 El Niño seasons (−0.2 °C on average) |
| Feb–Apr | Drier in 7 of 10 El Niño seasons (about 17% less rain on average) | Cooler in 8 of 10 El Niño seasons (−0.2 °C on average) |
| Mar–May | Drier in 6 of 8 El Niño seasons (about 19% less rain on average) | Cooler in 7 of 8 El Niño seasons (−0.3 °C on average) |
| Apr–Jun | No consistent pattern (about 14% less rain on average) | Cooler in 7 of 8 El Niño seasons (−0.4 °C on average) |
| May–Jul | No consistent pattern (about 18% less rain on average) | Cooler in 7 of 9 El Niño seasons (−0.4 °C on average) |
| Jun–Aug | No consistent pattern (about 9% less rain on average) | Cooler in 6 of 8 El Niño seasons (−0.5 °C on average) |
| Jul–Sep | No consistent pattern (about 9% more rain on average) | Cooler in 7 of 9 El Niño seasons (−0.5 °C on average) |
| Aug–Oct | No consistent pattern (about 9% less rain on average) | Cooler in 12 of 12 El Niño seasons (−0.6 °C on average) |
| Sep–Nov | Drier in 12 of 15 El Niño seasons (about 38% less rain on average) | Cooler in 15 of 15 El Niño seasons (−0.7 °C on average) |
| Oct–Dec | Drier in 12 of 15 El Niño seasons (about 42% less rain on average) | Cooler in 15 of 15 El Niño seasons (−0.6 °C on average) |
| Nov–Jan | Drier in 13 of 15 El Niño seasons (about 42% less rain on average) | Cooler in 11 of 15 El Niño seasons (−0.5 °C on average) |
Source: ERA5 monthly reanalysis (Copernicus Climate Change Service); El Niño seasons from NOAA's Oceanic Niño Index. Method.
Official warnings
Tonga Meteorological Services (Ministry of MEIDECC)
This is not an official forecast or warning. Seasonal outlooks give odds, not certainties. For warnings and decisions about safety, follow your national weather service.
What you can do
If it turns out drier
- Follow water-use notices from your local water utility, and fix leaks early.
- Farmers: check planting advice and drought bulletins from the national agriculture and weather services before the season.
- Clear dry vegetation near homes where wildfires are possible, and know your local fire-danger rating.
- Keep a few days of drinking water stored if supply cuts have happened in past dry years.
If it turns out hotter
- Check on older relatives, neighbours and anyone who lives alone during hot spells.
- Drink water regularly, and avoid hard outdoor work in the hottest hours.
- Know the signs of heat exhaustion (dizziness, headache, nausea) and when to get medical help.
Get a free alert when this changes
Country alerts start in December 2026. Check back here, or see the status page for the next official update dates.
Nearby countries
American Samoa · Cook Islands · French Polynesia · Samoa · Tuvalu · Wallis and Futuna Islands
Sources and dates
- El Niño status: NOAA Climate Prediction Center, 12 November 2026.
- Seasonal outlook: Copernicus Climate Change Service, Copernicus Climate Change Service (C3S) seasonal forecasts, ECMWF system 51, issued November 2026.
- Air quality: Copernicus Atmosphere Monitoring Service, run 2026-11-14 00 UTC.
- Past El Niños: ERA5 (Copernicus Climate Change Service), 1979-2025; NOAA Oceanic Niño Index.
Cite this page: “El Niño 2026–27 in Tonga”, El Niño Atlas, https://elninoatlas.pages.dev/country/tonga/, updated 15 November 2026.
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