The La Niña that followed the strong 1997/98 El Niño lasted 33 months, spanning three winters.
Notes on verification
Confirmed by NOAA Climate.gov FAQ (independent authoritative source) and corroborated by academic literature on the 1998-1999 La Niña event, which extended into 2000-2001, spanning three winters. [tier=silver indep_score=0.925 clusters=2 claim_tier=notable]
Sources
- Say Goodbye to a Historic El Niño and Hello to La Niña (seed:science_and_space)
- https://www.climate.gov/news-features/understanding-climate/el-nino-and-la-nina-frequently-asked-questions (corroboration)
- https://www.researchgate.net/publication/379169880_The_1998-1999_La_Nina_Event_Insights_from_Literature (corroboration)