Belgium recorded 2,935 excess deaths during a series of summer heatwaves between June 18 and August 16, 2026, according to new figures from the country’s public health agency Sciensano. The deaths represent a 22.6% increase in mortality compared with the number normally expected during the period, highlighting the severe health consequences of extreme heat across the country.
The figures, reported by Reuters on September 3, come after a summer marked by repeated episodes of unusually high temperatures across Europe. Belgium was among several European countries to experience intense heat, with the impacts extending beyond discomfort and temporary disruption into measurable increases in deaths.
Sciensano’s estimate covers the period from June 18 through August 16. Rather than referring only to deaths directly recorded as being caused by heat, the figure of 2,935 represents excess mortality, meaning the number of deaths above what would normally be expected based on baseline mortality patterns. This measure is widely used by public health authorities to assess the broader impact of extreme weather events because heat can worsen existing cardiovascular, respiratory and other health conditions without necessarily being listed as the immediate cause of death.
The scale of Belgium’s excess mortality is particularly significant because the country has a highly urbanised and densely populated population, conditions that can intensify exposure to heat. Previous research by Sciensano has highlighted the vulnerability of older people to heat-related mortality and warned that climate and demographic changes could increase the future health burden associated with high temperatures.
The Belgian numbers also form part of a wider European pattern this summer. Spain, for example, recorded an estimated 2,149 heat-related deaths in August alone, according to official data reported by Reuters on September 1. The figures from both countries illustrate how extreme heat is increasingly being reflected in national mortality statistics rather than simply appearing as a short-term weather emergency.
The European summer of 2026 has been characterised by a combination of extreme heat, drought, wildfires and unusually low river levels. Reuters reported on September 2 that more than 300,000 hectares had been affected by wildfires across countries including Spain, Italy, Portugal, France and Greece, while major European rivers including the Seine, Rhine and Danube reached exceptionally low levels. Extreme heat across the region was linked to nearly 10,000 excess deaths.
Belgium itself faced multiple climate-related pressures during the summer. The country's heatwaves occurred alongside other environmental stresses, including a major wildfire in Wallonia. The combination demonstrates why extreme heat is increasingly being treated as a systemic risk rather than an isolated weather event.
Heat can affect the human body in several ways. Prolonged exposure to high temperatures increases cardiovascular strain, contributes to dehydration and can worsen existing illnesses. Older people, people with chronic conditions and those living in poorly ventilated or inadequately cooled homes are particularly vulnerable. Outdoor workers and people without reliable access to cooling can also face elevated risks during prolonged heat events.
The health effects can also continue after temperatures begin to fall. Extreme heat can place substantial stress on the cardiovascular and respiratory systems, while vulnerable people may experience complications from underlying illnesses. This means the consequences of a heatwave cannot always be understood simply by counting deaths occurring on the hottest day.
Belgium has previously developed systems for monitoring excess mortality, allowing public health authorities to compare observed deaths with expected levels. Sciensano's mortality monitoring work has been used to identify periods when deaths rise significantly above normal levels and to examine potential relationships with environmental conditions.
The 2026 figures therefore provide more than a snapshot of one country's summer. They offer another indication of how climate-related hazards can translate into direct public health consequences. As heatwaves become more frequent, intense or prolonged, governments face increasing pressure to strengthen heat-health warning systems, protect vulnerable populations and adapt cities and buildings to higher temperatures.
Belgium's experience also raises questions about how European countries measure and communicate heat-related mortality. Directly attributed heat deaths are often only a fraction of the wider mortality impact because extreme temperatures can accelerate or worsen existing health problems. Excess mortality analysis provides a broader picture of the human cost.
The timing of the Belgian report is also important. It comes after a summer in which extreme weather repeatedly affected communities across Europe. Wildfires damaged ecosystems and infrastructure, drought reduced water availability, and heat placed additional pressure on energy systems and public health services. The combination is increasingly forcing policymakers to consider climate risks as interconnected rather than separate environmental problems.
The 2,935 excess deaths recorded in Belgium between June 18 and August 16 are consequently not just a statistic about a hot summer. They show how quickly extreme temperatures can become a public health emergency when heat persists across large populations.
For European governments, the challenge is moving from emergency response toward long-term heat resilience. That includes better early-warning systems, accessible cooling spaces, heat-resistant buildings, urban planning that reduces heat exposure and targeted protection for people most at risk.
Belgium's summer mortality figures provide another warning that the cost of extreme heat is not limited to melting roads, damaged crops or uncomfortable temperatures. It can also be measured in lives lost, and as climate change continues to raise global temperatures, that health burden is becoming increasingly difficult to ignore.