Belgium’s June heatwave produced the country’s deadliest heat episode since 2000

Updated 17 August 2026 — Brussels. Belgium recorded 1,747 more deaths than expected between 18 June and 1 July during the country’s June heatwave, Sciensano reported, making it the deadliest heat episode since the institute began monitoring excess mortality in 2000. The institute calculated a 47.8% rise above expected mortality across Belgium.

The human toll peaked on 27 June. Statbel’s later National Register extract counted about 650 deaths that day and about 640 on 28 June, among the highest daily totals recorded in Belgium this century. Statbel counted 9,741 deaths during June as a whole: 5,351 in Flanders, 3,582 in Wallonia and 808 in Brussels.

The Royal Meteorological Institute registered an official heatwave in Uccle from 17 to 28 June. Associated Press reporting, citing the institute, put the peak temperature at 35.5°C on 26 June. The prolonged heat included unusually warm nights, limiting the time in which bodies and buildings could cool.

Heat places additional strain on the heart, lungs and kidneys, with older people and those living with chronic illness facing the greatest danger. Sciensano nevertheless found excess mortality across every age group, including 280 additional deaths among people younger than 65, according to The Brussels Times. Death certificates do not always identify heat as the immediate cause, so researchers use all-cause mortality against a statistically expected baseline.

Belgium’s percentage increase was higher than those reported in several neighbouring countries. Het Nieuwsblad, using European mortality-monitoring data, reported excess mortality of about 48% in Belgium, compared with 23% in France and 13% in the Netherlands. Epidemiologist Geert Molenberghs told the newspaper that Belgium’s dispersed, poorly coordinated development pattern warranted examination because extensive paving, limited shade and heat-retaining buildings increase exposure. Sciensano has said no single explanation has been established, particularly for Wallonia’s high toll.

The episode followed the severe August 2020 heatwave, during which Sciensano measured 1,555 additional deaths. Belgium’s federal and regional health ministers have now instructed the Risk Management Group to develop a more integrated heat plan based on new World Health Organization guidance. The unresolved questions concern why mortality differed so sharply by region and how much housing, healthcare infrastructure, air pollution and access to cooling each contributed.