May 2026 was second warmest May on record, Copernicus says

The Copernicus Climate Change Service (C3S) reported that May 2026 was the second warmest May in recorded history, with a global average surface air temperat...

What Happened

The Copernicus Climate Change Service (C3S) reported that May 2026 was the second warmest May in recorded history, with a global average surface air temperature of 15.81°C — 0.55°C above the 1991–2020 reference average and 1.42°C above the pre-industrial baseline (1850–1900).
Only May 2024 was warmer, meaning the world has recorded its two hottest Mays in back-to-back years.
Sea surface temperatures (SSTs) between 60°S and 60°N were the second highest on record, with "exceptionally high" SSTs in the Equatorial Pacific signalling early El Niño development.
Europe experienced a rapid shift around May 20 from below-average to well above-average temperatures, with heat records broken in France, the UK, Ireland, and Portugal; "feels-like" temperatures reached 35–40°C across many locations.
Central and western Europe recorded below-average rainfall; below-normal river flows were observed across central, eastern, and northeastern Europe. Drought conditions also affected central United States, central Asia, Madagascar, southwest Australia, and parts of South America.
The World Meteorological Organization (WMO) assessed an 80% probability of El Niño formation between June and August 2026.

Static Topic Bridges

Copernicus Climate Change Service (C3S) and Earth Observation

C3S is one of six thematic services under the European Union's Copernicus Earth Observation Programme. It is implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Commission. C3S integrates data from satellites, land stations, ocean buoys, and radiosondes to provide consistent, authoritative climate data free and open to all users globally.

Established under the Copernicus Programme, the EU's flagship Earth observation initiative alongside services for atmosphere (CAMS), marine (CMEMS), land, emergency management, and security.
ECMWF, based in Reading, UK, is an intergovernmental organisation supported by 35 states; it runs the world's most accurate medium-range weather forecasts.
C3S publishes monthly global temperature bulletins and the annual European State of the Climate report, which are the reference datasets for IPCC assessments and UNFCCC stocktakes.
Data is freely accessible through the Climate Data Store (CDS), a key global public good.

Connection to this news: The record-temperature finding is based on C3S data, making understanding the institution critical for UPSC questions that ask about the source and reliability of global climate records.

The 1.5°C Threshold and the Paris Agreement Baseline

The Paris Agreement (2015) sets a long-term goal of limiting global average temperature rise to well below 2°C above pre-industrial levels, with efforts to limit it to 1.5°C. The "pre-industrial" period is operationally defined as 1850–1900 — the earliest period with sufficient instrumental records — and serves as the reference against which current warming is measured.

The 1.5°C threshold was incorporated into the Paris Agreement partly due to advocacy by Small Island Developing States (SIDS) and Least Developed Countries (LDCs), who argued that 2°C would be existential for low-lying nations.
A single month above 1.5°C does not constitute a breach of the Paris Agreement limit, which refers to long-term (multi-decadal) average warming.
The IPCC Sixth Assessment Report (AR6, 2021–22) found that human influence has already warmed the climate by approximately 1.1°C above the 1850–1900 baseline.
Scientists note that the planet may cross the 1.5°C long-term threshold within the next decade at current emission trajectories.
The 2°C limit is associated with significantly more severe impacts: more extreme heatwaves, greater sea level rise, loss of coral reefs, and increased frequency of extreme weather events.

Connection to this news: May 2026's anomaly of 1.42°C brings monthly temperatures close to — but still short of — a sustained breach of 1.5°C. This illustrates why the Paris threshold is a scientific and policy red line, not merely a target.

Heat Domes, Drought, and Climate Feedback Mechanisms

A heat dome occurs when a high-pressure system traps hot air over a region, causing temperatures to rise far above seasonal norms. When combined with drought conditions (below-average soil moisture reduces evaporative cooling), heat domes produce compounding extreme events. Climate change increases the frequency, intensity, and duration of heat domes by raising the baseline temperature from which anomalies develop.

Europe's rapid temperature shift in late May 2026 was consistent with a heat dome pattern driven by an anomalous blocking high-pressure ridge.
Drought reduces latent heat flux (evaporation), diverting more solar energy into sensible heat, which further amplifies temperatures — a well-documented land-atmosphere feedback.
River flow deficits in central and northeastern Europe directly threaten hydropower generation, inland navigation, and agricultural irrigation.
Climate models project that events like the European heatwave of 2026 will become 2–5 times more frequent by mid-century under a 2°C warming scenario.

Connection to this news: The co-occurrence of Europe's heat dome and widespread drought in May 2026 is a textbook illustration of compounding climate extremes — directly relevant to GS3 questions on extreme weather events and climate change impacts.

Sea Surface Temperatures and Ocean Heat Content

The oceans absorb more than 90% of the excess heat trapped by greenhouse gases in the atmosphere. Sea Surface Temperature (SST) anomalies in the equatorial Pacific are the primary metric used to declare El Niño or La Niña conditions. Exceptionally high global SSTs in 2026 reflect both long-term ocean heat accumulation and the transition to an El Niño phase.

Ocean heat content (OHC) has reached record highs in recent years, with the upper 2,000 metres of the world's oceans consistently breaking records since 2018.
SSTs in the North Atlantic reached unprecedented levels in 2023–24, contributing to above-normal Atlantic hurricane seasons.
Warm SSTs accelerate coral bleaching (loss of zooxanthellae symbiotic algae) when sustained above ~1°C above the local bleaching threshold.
The Southern Oscillation Index (SOI) — the atmospheric pressure difference between Tahiti and Darwin — is the standard measure of ENSO phase, complementing SST anomalies (Niño 3.4 index).

Connection to this news: May 2026's second-highest global SSTs and "exceptionally high" equatorial Pacific SSTs are both the driver and the indicator of the emerging El Niño, whose monsoon implications for India are severe.

Key Facts & Data

May 2026 global average surface air temperature: 15.81°C (0.55°C above the 1991–2020 average; 1.42°C above the 1850–1900 pre-industrial baseline).
Rank: Second warmest May on record; warmest was May 2024.
Sea surface temperatures: Second highest on record (60°S–60°N), exceptionally high in the Equatorial Pacific.
European temperature records broken in May 2026: France, UK, Ireland, Portugal.
"Feels-like" temperatures during Europe's heat dome: 35–40°C across many locations.
WMO El Niño probability (June–August 2026): 80%.
Drought regions: Central/western Europe, central US, central Asia, Madagascar, southwest Australia, parts of South America.
Paris Agreement 1.5°C baseline: 1850–1900 average global temperature.
C3S is implemented by ECMWF on behalf of the European Commission under the Copernicus Programme.