In general, the warmest year of any decade will be an El Niño year, the coldest a La Niña one. This graph shows annual average surface temperatures (gray bars), grouped by decade, from 1950 to 2021. The warmest and coldest years of each decade are topped with circles: red for El Niño-influenced years and blue for La Niña years. We considered a year El Niño or La Niña "influenced" if the December-February was labelled as part of a historical episode by NOAA's Climate Prediction Center or if more than half of the months in that year were. By our definition, 1979 did not qualify as El Niño year because El Niño conditions were present for only 3 months late in the year. 1992 was the coldest year of the 1990s despite being an El Niño year because of the cooling influence of the eruption of Mount Pinatubo in 1991. NOAA Climate.gov graph based on data from NOAA National Centers for Environmental Information.
