The 2003 Heat Wave That Killed More People Than Most Modern Wars

A single summer season killed more people across Europe than most wars fought on the continent since 1945. The 2003 European heat wave remains one of the deadliest weather disasters in modern history, and it fundamentally reshaped how European countries prepare for extreme heat today.

How Hot Did It Get

The heat wave stretched from June through mid-August 2003, driven by a persistent area of high pressure parked over western Europe that blocked rain and let temperatures climb for weeks on end. Average summer temperatures ran 3 to 5 degrees Celsius above normal across southern and central Europe, with the hottest stretch between August 1 and 13, when anomalies reached 7 degrees Celsius above average in some areas.

The single hottest temperature recorded was 117.1°F (47.3°C) in Amareleja, Portugal, on August 1, 2003. France saw temperatures near 99°F (37°C) hold steady for more than a week in some regions, with Paris recording highs at or above 95°F (35°C) for nearly two weeks straight. The United Kingdom hit an all-time national record of 100.4°F (38.5°C) in Kent, its first-ever officially recorded reading above 100°F.

What made the heat so dangerous wasn't just the daytime highs. Nighttime temperatures stayed unusually elevated too, denying homes and bodies the normal overnight cooldown that much of Europe relies on instead of air conditioning.