Brussels, 19 June 2025 — Belgium’s Interregional Environment Cell (CELINE) has activated the warning phase of the High Heat and Ozone Peaks Plan starting Thursday, amid forecasts of a prolonged spell of hot weather and rising ozone levels.
The Royal Meteorological Institute (IRM) predicts that temperatures will surpass 28°C at the Uccle reference station from Friday, 20 June, triggering the threshold for heat alert procedures.
Today, highs of up to 27°C are expected across the country. Over the coming weekend, maximum temperatures could range from 25°C in coastal regions to a sweltering 32°C in central areas, including Brussels. This early summer heatwave is accompanied by a steady rise in ozone concentrations in the lower atmosphere.
While the IRM notes that ozone levels are expected to increase, they should remain below the European Union’s public information threshold of 180 micrograms per cubic metre (µg/m³), the point at which health warnings are issued for the general population.
The activation of the warning phase serves as a preventative step aimed at informing citizens, healthcare professionals, and care workers.
CELINE stresses the importance of taking precautions, particularly for vulnerable groups such as the elderly, infants, people with chronic health conditions, and those living alone.
“The warning phase is not a sign of immediate danger but an opportunity to prepare and protect those at risk,” a CELINE spokesperson said.
“We advise people to monitor indoor temperatures, ensure access to fresh drinking water, and check in on relatives, neighbours, and friends, especially those who may not be able to care for themselves.”
Authorities are urging people to avoid strenuous outdoor activities during peak sunlight hours, stay hydrated, wear light clothing, and keep their living spaces cool. In cities, where heat can intensify due to the urban heat island effect, the risks are even more pronounced.
Although the ozone concentration is not expected to exceed the EU’s threshold, health professionals warn that even moderate levels of ozone can aggravate respiratory conditions such as asthma and bronchitis. Children playing outdoors and those engaging in physical activities are particularly susceptible.
Hospitals and care centres have been briefed to remain alert, and municipalities may implement additional measures such as cooling zones or extended public swimming pool hours if the heat persists beyond the weekend.
This is the first major heat episode of the summer season, and it comes earlier than usual, raising concerns about the potential for more extreme weather in the coming weeks.
The IRM and CELINE will continue to monitor both temperature and ozone levels closely and provide regular updates. Citizens are encouraged to follow official channels for the latest advisories and take personal responsibility to mitigate the health impacts of the heat.
With Europe bracing for a hotter-than-average summer, Belgian authorities are emphasising early vigilance and community solidarity as key defences against heat-related health risks.
