Extreme heat, record temperatures dominate 2025
The year 2025 ranked among the warmest on record globally, marked by extreme heat, record temperatures and widespread impacts, according to the World Meteorological Organization (WMO) and the Copernicus Climate Change Service.
Global temperatures were the second or third highest ever recorded, despite a shift toward neutral or weak La Niña conditions that would normally cool the climate. Scientists said rising greenhouse gas emissions continue to drive long-term warming, overwhelming natural cooling cycles.
The WMO warned that temperatures over the next five years are likely to remain near record levels, with an 80% chance that at least one year will surpass the current warmest year and a 70% likelihood that the five-year average will temporarily exceed 1.5 degrees Celsius above pre-industrial levels.
Summer 2025 brought intense heatwaves across much of the world, with July ranking as the third-warmest on record globally. Europe experienced its fourth-warmest summer, with land surface temperatures up to 6C above average in parts of Spain, France, the Balkans and northern Europe.
The UK recorded its hottest June on record in England, while Spain endured its most intense heatwave in August. Prolonged heat also affected Scandinavia.
A study by Imperial College London and the London School of Hygiene & Tropical Medicine estimated about 24,400 heat-related deaths across European cities between June and August, with around two-thirds attributed to climate change. Italy recorded the highest toll, followed by Spain, Germany, France and the UK. Most victims were aged 65 or older.
Asia and North America
Large parts of Asia were hit by extreme heat. Japan saw one of its hottest Junes since records began, South Korea reported record temperatures, and parts of India and Pakistan experienced temperatures near 50C. Iran closed public institutions in multiple provinces to manage soaring energy demand.
In North America, a major heat dome in June exposed more than 255 million people in the United States to extreme temperatures. The Centers for Disease Control and Prevention reported at least 150 heat-related deaths, with power grids and health systems under strain.
Drought risks rise
Extreme heat worsened drought conditions worldwide by accelerating evaporation. Iran faced a severe water crisis, while drought also affected parts of the Middle East, Africa and East Asia. The WMO warned of increasingly erratic water cycles, with rapid shifts between floods and droughts.
The events of 2025 highlighted the growing and accelerating risks of climate change, with heatwaves and droughts becoming more frequent, severe and disruptive across the globe.
