Science1998-2001globalhigh confidence

The La Niña following the unusually strong 1997/98 El Niño lasted 33 months and spanned three winters.

Notes on verification

Multiple reputable sources (WMO, NASA, NC State) confirm the 1998-2001 'triple-dip' La Niña spanning three winters, but the exact figure of 33 months was not independently verified in precise wording, though it is consistent with the confirmed timeframe. [tier=gold indep_score=0.747 clusters=3 claim_tier=notable]

Sources