La Niña 2021-2023
La Niña 2021-2023 lasted about 19 months, from Aug–Oct 2021 to Dec–Feb 2023. The Oceanic Niño Index peaked at -0.9 °C in OND 2021, a weak La Niña, ranked #15 of 20 since 1950.
StartASO 2021Aug–Oct
EndDJF 2023Dec–Feb
Duration19 months17 seasons
Peak ONI-0.9 °COND 2021
Average ONI-0.77 °Cduring the episode
StrengthWeak#15 / 20
What happened
Second and third winters of the "triple-dip" La Niña of 2020-2023; drought in Argentina, Uruguay and the Horn of Africa.
Impacts vary by region and event; see our country pages for the usual pattern.
ONI before, during and after La Niña 2021-2023
Season by season
| Season | Year | ONI | Niño 3.4 temp. |
|---|---|---|---|
| ASO Aug–Oct | 2021 | -0.6 °C | 26.13 °C |
| SON Sep–Nov | 2021 | -0.8 °C | 25.94 °C |
| OND Oct–Dec | 2021 | -0.9 °C | 25.74 °C |
| NDJ Nov–Jan | 2021 | -0.8 °C | 25.73 °C |
| DJF Dec–Feb | 2022 | -0.8 °C | 25.79 °C |
| JFM Jan–Mar | 2022 | -0.7 °C | 26.09 °C |
| FMA Feb–Apr | 2022 | -0.8 °C | 26.46 °C |
| MAM Mar–May | 2022 | -0.9 °C | 26.77 °C |
| AMJ Apr–Jun | 2022 | -0.8 °C | 26.96 °C |
| MJJ May–Jul | 2022 | -0.7 °C | 26.90 °C |
| JJA Jun–Aug | 2022 | -0.7 °C | 26.59 °C |
| JAS Jul–Sep | 2022 | -0.8 °C | 26.18 °C |
| ASO Aug–Oct | 2022 | -0.9 °C | 25.89 °C |
| SON Sep–Nov | 2022 | -0.9 °C | 25.82 °C |
| OND Oct–Dec | 2022 | -0.8 °C | 25.83 °C |
| NDJ Nov–Jan | 2022 | -0.7 °C | 25.86 °C |
| DJF Dec–Feb | 2023 | -0.6 °C | 26.00 °C |
Compare with other episodes
Frequently asked questions
When did La Niña 2021-2023 start and end?
It started in ASO 2021 and ended in DJF 2023, about 19 months.
How strong was La Niña 2021-2023?
Its peak ONI was -0.9 °C (OND 2021), classified as weak. It ranks #15 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.