El Niño 2009-2010
El Niño 2009-2010 lasted about 11 months, from Jun–Aug 2009 to Feb–Apr 2010. The Oceanic Niño Index peaked at +1.5 °C in NDJ 2009, a strong El Niño, ranked #10 of 23 since 1950.
StartJJA 2009Jun–Aug
EndFMA 2010Feb–Apr
Duration11 months9 seasons
Peak ONI+1.5 °CNDJ 2009
Average ONI+1.00 °Cduring the episode
StrengthStrong#10 / 23
ONI before, during and after El Niño 2009-2010
Season by season
| Season | Year | ONI | Niño 3.4 temp. |
|---|---|---|---|
| JJA Jun–Aug | 2009 | +0.5 °C | 27.82 °C |
| JAS Jul–Sep | 2009 | +0.6 °C | 27.55 °C |
| ASO Aug–Oct | 2009 | +0.7 °C | 27.46 °C |
| SON Sep–Nov | 2009 | +0.9 °C | 27.68 °C |
| OND Oct–Dec | 2009 | +1.3 °C | 28.02 °C |
| NDJ Nov–Jan | 2009 | +1.5 °C | 28.16 °C |
| DJF Dec–Feb | 2010 | +1.5 °C | 28.15 °C |
| JFM Jan–Mar | 2010 | +1.2 °C | 28.11 °C |
| FMA Feb–Apr | 2010 | +0.9 °C | 28.22 °C |
Compare with other episodes
← El Niño 2006-2007El Niño 2014-2016 →La Niña 2008-2009La Niña 2010-2011El Niño 2026 (current)
Frequently asked questions
When did El Niño 2009-2010 start and end?
It started in JJA 2009 and ended in FMA 2010, about 11 months.
How strong was El Niño 2009-2010?
Its peak ONI was +1.5 °C (NDJ 2009), classified as strong. It ranks #10 among 23 El Niño episodes since 1950.
How does it compare with the current El Niño?
The current event (El Niño 2026) has reached +2.5 °C so far, above the +1.5 °C peak of El Niño 2009-2010.
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.