May 2026 was world's second-warmest May on record, EU climate service reports

Samantha Burgess, an expert at the European Centre for Medium-Range Weather Forecasts (ECMWF), said the data confirmed an ongoing pattern. „In May 2026, exceptional global warming continued, with atmospheric and ocean temperatures reaching near-record levels," she said. The May reading places the month just behind the warmest May in the modern record, the service reported.

An unusually early heatwave in Western Europe

In Europe, the month was defined by a rapid shift from below-average temperatures early in May to one of the most intense heatwaves ever observed so early in the year across Western Europe. France, the United Kingdom, Ireland and Portugal were particularly affected, and the heatwave caused numerous monthly temperature records to be broken across the region.

Burgess described the European heat episode as a sign of how quickly extremes are being absorbed into baseline weather. „In Europe, an unusually early and intense heatwave shows how quickly climate extremes are becoming the new normal rather than the exception," she said.

Warm oceans and a developing El Niño

The Copernicus service also pointed to exceptionally high sea-surface temperatures in the tropical Pacific during May 2026, as the equatorial Pacific continued to move toward El Niño conditions. The combination of warm oceans and warm air helped push the global monthly average close to the historical high.

Outside Europe, the month brought a contrasting mix of rainfall. Above-average precipitation fell across northern and southeastern North America, parts of Asia north of the Indian subcontinent, parts of West China, areas of Brazil, southern Africa, and large parts of Australia, according to the bulletin. The pattern underlined how heat and precipitation extremes are increasingly appearing in the same months.

A long-term trend toward more intense extremes

The May 2026 reading fits a long-term trend identified by the climate service: warming in Europe is accelerating, and heatwaves are becoming more frequent, more intense, and arriving earlier in the year. The service has repeatedly linked such shifts to the continued accumulation of greenhouse gases in the atmosphere.

The findings add to a string of recent monthly bulletins from Copernicus documenting record or near-record conditions. The agency, headquartered in Bonn, draws on satellite data, in-situ measurements, and numerical models to produce its global climate assessments, which are widely used by European institutions, national meteorological agencies, and researchers.

Burgess and other ECMWF experts frame the May data as further evidence that warming is not limited to single hot seasons but is now embedded in the climate system. The report is expected to feed into discussions at European and international level about adaptation measures, early-warning systems, and the pace of emissions reductions.

The heatwave of May 2026 was the latest in a series of extreme heat events that scientists have attributed to human-induced climate change. Across the four hardest-hit countries, public health authorities reported increased strain on hospitals, transport disruptions, and pressure on energy grids during the hottest days, though the Copernicus bulletin itself focuses on the climatic measurements rather than the human impact.