Belgium faces its hottest stretch of the heatwave as France’s 40C surge moves north

Belgium is entering the most dangerous phase of a western European heatwave that has already pushed parts of France above 40C and put public-health systems, transport operators and city authorities on alert. For Belgium-based readers, the immediate issue is not only the daytime maximum: the Royal Meteorological Institute says inland temperatures may reach 36C to 38C, locally 39C on Friday, while some large urban areas may stay at 25C to 27C overnight. That is the threshold at which heat stops being a hot afternoon and becomes a recovery problem, especially for older people, small children, outdoor workers and people living in poorly insulated flats. The SPF Public Health alert phase of Belgium’s ozone and heat plan remains active, according to the IRM’s warning page. In practical terms, this means drinking before feeling thirsty, checking on vulnerable neighbours, limiting sport and outdoor work in the hottest hours, and following local instructions from communes, Brussels services, hospitals, care homes and employers. The international picture explains why Belgium is exposed. France has seen temperatures above 40C and widespread red heat alerts, with disruption to schools, tourist sites and infrastructure. The same hot air mass is affecting Spain, Italy, the Netherlands, Germany and the United Kingdom, while the European Meteoalarm system provides cross-border warning coordination. Francophone Belgian coverage has framed the question as “comment la canicule va-t-elle frapper la Belgique” after “40C en France” and “records attendus” at home; the answer is that Belgium is less exposed than south-west France, but still faces an unusually early, intense and humid heat episode, followed by a growing risk of thunderstorms. The broader lesson is that heatwaves are no longer a southern European exception. The IRM says Belgium’s early and intense heat fits a trend toward more frequent and extreme heat peaks in recent decades. That does not make every record automatic, but it changes the baseline for public services: schools, trains, care homes, offices and city housing now need heat plans, not improvised advice. What happens next depends on two things: whether Friday’s projected peak reaches record territory at Uccle, and whether Saturday’s unstable air produces storms strong enough to create a second risk after the heat.