La Niña 2020-2021
La Niña 2020-2021 lasted about 10 months, from Aug–Oct 2020 to Mar–May 2021. The Oceanic Niño Index peaked at -1.1 °C in OND 2020, a moderate La Niña, ranked #10 of 20 since 1950.
What happened
First winter of the rare "triple-dip" La Niña of 2020-2023, three consecutive La Niña winters.
Impacts vary by region and event; see our country pages for the usual pattern.
ONI before, during and after La Niña 2020-2021
Season by season
| Season | Year | ONI | Niño 3.4 temp. |
|---|---|---|---|
| ASO Aug–Oct | 2020 | -0.8 °C | 25.99 °C |
| SON Sep–Nov | 2020 | -1.0 °C | 25.71 °C |
| OND Oct–Dec | 2020 | -1.1 °C | 25.54 °C |
| NDJ Nov–Jan | 2020 | -1.1 °C | 25.50 °C |
| DJF Dec–Feb | 2021 | -1.0 °C | 25.55 °C |
| JFM Jan–Mar | 2021 | -0.8 °C | 25.92 °C |
| FMA Feb–Apr | 2021 | -0.7 °C | 26.48 °C |
| MAM Mar–May | 2021 | -0.6 °C | 27.07 °C |
Compare with other episodes
← La Niña 2017-2018La Niña 2021-2023 →El Niño 2019-2020El Niño 2026 (current)
Frequently asked questions
When did La Niña 2020-2021 start and end?
It started in ASO 2020 and ended in MAM 2021, about 10 months.
How strong was La Niña 2020-2021?
Its peak ONI was -1.1 °C (OND 2020), classified as moderate. It ranks #10 among 20 La Niña episodes since 1950.
Episodes are computed from NOAA's Oceanic Niño Index (ERSSTv5) with the standard rule: five or more consecutive overlapping seasons at or beyond ±0.5 °C. Free to cite with a link to elninoforecast.com.