El Niño 2004-2005
El Niño 2004-2005 lasted about 9 months, from Jul–Sep 2004 to Jan–Mar 2005. The Oceanic Niño Index peaked at +0.7 °C in NDJ 2004, a weak El Niño, ranked #23 of 23 since 1950.
StartJAS 2004Jul–Sep
EndJFM 2005Jan–Mar
Duration9 months7 seasons
Peak ONI+0.7 °CNDJ 2004
Average ONI+0.61 °Cduring the episode
StrengthWeak#23 / 23
ONI before, during and after El Niño 2004-2005
Season by season
| Season | Year | ONI | Niño 3.4 temp. |
|---|---|---|---|
| JAS Jul–Sep | 2004 | +0.5 °C | 27.53 °C |
| ASO Aug–Oct | 2004 | +0.6 °C | 27.40 °C |
| SON Sep–Nov | 2004 | +0.6 °C | 27.38 °C |
| OND Oct–Dec | 2004 | +0.6 °C | 27.37 °C |
| NDJ Nov–Jan | 2004 | +0.7 °C | 27.34 °C |
| DJF Dec–Feb | 2005 | +0.6 °C | 27.23 °C |
| JFM Jan–Mar | 2005 | +0.6 °C | 27.35 °C |
Compare with other episodes
← El Niño 2002-2003El Niño 2006-2007 →La Niña 2005-2006El Niño 2026 (current)
Frequently asked questions
When did El Niño 2004-2005 start and end?
It started in JAS 2004 and ended in JFM 2005, about 9 months.
How strong was El Niño 2004-2005?
Its peak ONI was +0.7 °C (NDJ 2004), classified as weak. It ranks #23 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 +0.7 °C peak of El Niño 2004-2005.
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.