El Niño lends heat from the ocean to the atmosphere: global mean temperature tends to set records in the year after the peak — as in 1998, 2016 and 2024. With an event of this size on an already warmer planet, every day of 2026 and 2027 is compared here with the previous years (SST since 1981; air since 1940, charted from 1981).

Sea surface temperature — global mean (60°S–60°N)

Daily anomaly relative to 1991–2020 (OISST v2.1, via Climate Reanalyzer). Each line is a year.

2 m air temperature — global mean

Daily anomaly relative to 1991–2020 (ERA5 reanalysis, via Climate Reanalyzer).