Image caption
Sea surface temperature in the Niño-3.4 region of the tropical Pacific from 1900 to 2023. Monthly data have been smoothed with a 5-month running mean after removing a seasonal climatology for 1981-2010. Red peaks are El Niño events and blue troughs La Niña events. The approximate mid-point of the time series is indicated by the vertical black line in 1960. The white area between ±0.5°C signifies neutral conditions. Data is from HadISST, which uses satellites and other in situ observational data.