enso-match-score-during-december-january-february-time-series.png

Time series of the Match score (green line) and ENSO (Oceanic Niño Index (ONI); black line) for past December-February winters from 1959-2024. Positive values of ONI (>= 0.5° C) are generally considered El Niño events and larger positive ONI values are stronger El Niños. Negative values of ONI (<= -0.5° C) are generally considered La Niña and larger, more negative ONI values are stronger La Niñas. The match score can range from +1 to -1. Larger more positive match scores indicate winters when the precipitation anomaly pattern looked more like the expected El Niño pattern. Larger more negative match scores mean that winter resembled the expected La Niña pattern. Map by climate.gov based on analysis by M. L’Heureux (reference).