December SST data from @NOAANCEI shows a one-month change of as much as -1°C in the eastern tropical Pacific, taking the Niño1+2 anomaly to its lowest value in N Hemisphere winter since Dec 2007 (and before that Dec 1975). Clear east-based #LaNina signature. pic.twitter.com/S0L8bNI3xN

— World Climate Service (@WorldClimateSvc) January 3, 2022