May 2026 recorded an average global surface temperature of 15.81°C, making it the second hottest May on record after May 2024. This was 0.55°C above the 1991-2020 average and 1.42°C above pre-industrial levels [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]. Sea surface temperatures were also the second highest on record for May, just below the peak seen in 2024 [1, 3, 4, 5, 6, 8, 10].
Western Europe experienced an unusually early and intense heatwave in May, setting record temperatures in France, the UK, Ireland, and Portugal. Feel-like temperatures reached 35-40°C in some areas, causing rapid warming and little time for people, crops, or ecosystems to adapt [1, 2, 3, 4, 5, 6, 8, 10]. Samantha Burgess, ECMWF climate strategic lead, said, "This unusually early and intense heat wave demonstrates how quickly climate extremes are becoming the new normal rather than the exception" [6].
Tropical Pacific sea surface temperatures remained anomalously high, showing continued transition toward an El Niño event expected to form in the coming months [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]. The World Meteorological Organization estimated an 80% chance of El Niño formation between June and August 2026 [3, 4, 5, 10]. NOAA confirmed the official formation of an El Niño event on June 11 and forecast it to strengthen through the end of the year, with a 63% chance of a very strong event developing between November 2026 and January 2027 [11, 12].
Carlo Buontempo, Copernicus Climate Change Service director, stated, "Current indications strongly suggest that this year will see a moderate to strong, possibly record-breaking El Niño event" [12]. Previous El Niño years such as 2023 and 2024 have led to some of the hottest years on record, amplifying global temperatures by adding ocean heat to the atmosphere [3, 4, 5, 10].
Arctic sea ice extent in May 2026 was about 4% below average, ranking as the fourth lowest May extent on record. Antarctic sea ice extent was about 9% below average, the seventh lowest since records began [1, 6]. Some parts of Europe saw drier conditions in the south and west, while northern and Scandinavian regions experienced wetter than average weather [6].
The EU’s Copernicus Climate Change Service and ECMWF reported on June 10 that May 2026’s data confirms the second hottest May globally and the growing norm of climate extremes in Europe [1, 3, 4, 5, 6, 10]. NOAA's announcement of El Niño formation on June 11 signals likely added global warming effects into late 2026 and early 2027 [11, 12].
