Geneva: 2025 ranked among the warmest years on record globally, despite a shift toward neutral or weak La Nina conditions that typically cool global temperatures, according to the World Meteorological Organization (WMO) and the Copernicus Climate Change Service. Global temperatures in 2025 ranked second or third warmest on record, following the record-hot year of 2024, underscoring the growing strength of human-caused warming driven by greenhouse gas emissions.
According to Anadolu Agency, scientists said natural cooling cycles are no longer sufficient to offset rising baseline temperatures, with many regions recording record or near-record heat levels throughout the year. The WMO stated that its latest global climate outlook shows temperatures over the next five years are likely to remain at or near record levels, with an 80% chance that at least one year will exceed the current warmest year on record and a 70% chance that the five-year average will temporarily exceed 1.5°C above pre-industrial levels.
The summer of 2025 was marked by extreme heatwaves, causing widespread health impacts and record temperatures across multiple regions. July ranked as the third-warmest on record globally. Europe, for instance, recorded its fourth-warmest summer on record, with intense heat concentrated in western and southern areas. Land surface temperatures were significantly above average in northeastern Spain, southwestern France, the Balkans, and parts of Fennoscandia, with anomalies reaching up to 6°C in some locations.
The UK experienced its hottest June on record in England and the second-warmest nationwide since records began in 1884, according to the Met Office. The Netherlands saw its second-highest June temperatures since 1901, data from the Royal Netherlands Meteorological Institute showed. Spain endured its most intense heatwave on record in August, as reported by the State Meteorological Agency. Scandinavia experienced prolonged heatwaves in July, with temperatures well above seasonal averages across the region.
A study by researchers from Imperial College London and the London School of Hygiene and Tropical Medicine estimated around 24,400 heat-related deaths across 854 European cities between June and August. Approximately 68% of those deaths were attributed to climate change, effectively tripling the expected toll without human-induced warming. Italy recorded the highest number of climate-attributed deaths, followed by Spain, Germany, France, and the UK.
In Asia, extreme heat affected large parts of the continent. Japan recorded one of its hottest Junes since records began, with prolonged heat leading to a surge in heatstroke cases and deaths, particularly among elderly people. South Korea reported record daily temperature averages in late June, the highest since 1904. India issued red alerts in New Delhi, while Pakistan saw temperatures rise to around 50°C in parts of Punjab province. In Iran, authorities closed public institutions in 18 provinces to manage soaring energy demand caused by widespread cooling system usage.
The US and parts of North America experienced severe heatwaves, including a major June heat dome that exposed more than 255 million people to extreme temperatures, frequently exceeding 38°C. Record heat affected the Midwest, Northeast, South, and West, leading to thousands of heat-related illnesses. The Centers for Disease Control and Prevention confirmed at least 150 heat-related deaths nationwide in 2025.
Drought conditions intensified as extreme heat increased evaporation rates. Iran faced one of its most severe water crises, with Lake Urmia shrinking dramatically and low dam levels in major cities. Droughts also affected Syria, parts of Africa, and South Korea. The WMO's State of Global Water Resources report warned of increasingly erratic water cycles, while UN Water projected that more than 5 billion people will face inadequate access to water for at least one month each year by 2050.
Events in 2025 underscored the accelerating risks posed by climate change, with heatwaves, droughts, and related crises becoming more frequent and severe worldwide.