Belgium Heatwave Led to 44 More Suspicious Deaths in June

Belgium’s record-breaking June heatwave resulted in 44 more “suspicious deaths” compared to the same period last year, according to data from the Leuven Forensic Medical Institute. The institute recorded 90 forensic investigations in June 2026, nearly double the 46 conducted in June 2025, while judicial autopsies surged from 11 to 29 — a near-tripling. The findings, reported by Het Laatste Nieuws, highlight the hidden toll of extreme heat beyond direct heat-related fatalities.

The Deadliest Heatwave on Record

The June 2026 heatwave was the most severe ever recorded in Belgium. Lasting 12 consecutive days from 18 to 29 June, it brought seven tropical days above 30°C and a peak of 35.5°C in Ukkel on 26 June. Exceptionally warm nights, with minimums above 18°C for ten nights and two nights near 24°C, prevented buildings from cooling down, compounding the health impact.

According to Sciensano, Belgium’s national health research institute, the heatwave caused approximately 2,000 excess deaths — a 48% excess mortality rate, the highest since records began in 2000. The deadliest day was 27 June, with 641 deaths recorded, representing 146.5% excess mortality. Normal daily deaths for late June are approximately 260.

Surge in Forensic Investigations

Suspicious deaths are cases where the cause of death is not immediately apparent as natural, requiring forensic investigation. Wouter Van Den Bogaert, head of the Leuven Forensic Medical Institute, described the unprecedented workload: “On average, we conducted three forensic investigations per day, while in a normal June it’s usually one.” During the peak period from 25 June to 1 July, his team performed up to six investigations in a single night.

“The files kept coming in,” Van Den Bogaert told HLN, describing the grueling conditions. Forensic doctors worked multiple consecutive night shifts, investigating deaths in attics where temperatures reached 30°C and bodies had been decomposing for days.

Why the Increase? Multiple Factors at Play

The rise in suspicious deaths stems from several interconnected factors. While a minority of victims died from direct hyperthermia (overheating), most were vulnerable individuals — often elderly people with chronic heart or lung conditions — for whom extreme heat proved fatal.

However, forensic doctors noted a troubling second trend: a significant increase in fatal risk-taking among people under 45. Drowning deaths rose as people sought cooling in rivers, canals, and unguarded swimming spots, underestimating the risks. Drug and alcohol intoxications also increased, with substances like MDMA raising body temperature and compounding the effects of heat. Additionally, fatal accidents — falls from heights, impulsive actions, and violence incidents — became more frequent. International studies cited by Van Den Bogaert show that crime, particularly violence and fights, increases by approximately 10% during extreme heat.

The Zorgcentrum na Seksueel Geweld (Care Center after Sexual Violence) in Leuven reported a sharp increase in victims during the heatwave period: 39 victims compared to 25 in the preceding month. Dr. Joke Wuestenbergs, a forensic medicine specialist, said: “We clearly see an increase, but today we cannot explain exactly what causes it.”

Regional Disparities and Younger Victims

Wallonia was hardest hit with 76% excess mortality (919 extra deaths), followed by Brussels at 60.9% (159 extra deaths), and Flanders at 31.4% (682 extra deaths), according to Sciensano. The reasons for these regional differences remain unclear, as Sciensano’s Be-MOMO monitoring system cannot attribute causes.

Strikingly, significant excess mortality was recorded among people under 65, with 280 extra deaths (61.3% excess mortality). This is unusual, as heatwaves typically affect the elderly most severely. The finding underscores that extreme heat poses a threat to all age groups.

Policy Response and Forward Look

The Belgian government has initiated a multi-pronged response. The Risk Management Group (RMG), as reported by the Federal Public Service for Public Health, maintained the warning phase for potential new heatwaves and established a working group for short-term measures. The Interministerial Conference on Public Health has tasked authorities with developing a multisectoral plan to strengthen preparation for future heatwaves.

With climate change increasing the frequency and intensity of heatwaves, the June 2026 disaster raises urgent questions about Belgium’s long-term preparedness. As VRT NWS reported, Sciensano extended its monitoring period by two days because excess mortality remained significantly higher than expected even after the heatwave ended. The full toll of indirect deaths — and the lessons to be learned — may take months to fully understand.