Belgium Confirms Second National Heatwave of 2026
Belgium has officially confirmed its second national heatwave of 2026, as temperatures in Ukkel reached 30.1°C on Tuesday, August 4. The VRT NWS liveblog reported that the reading at the national reference station officially triggered the criteria for a nationwide heatwave, which began on July 28 and has now lasted eight days.
What Defines a National Heatwave
The Royal Meteorological Institute (KMI) defines a national heatwave as occurring when temperatures in Ukkel reach at least 25°C for five consecutive days, with at least three of those days reaching 30°C or more. Ukkel serves as the reference point for determining national heatwave status in Belgium.
According to Meteovista, this is the 52nd official heatwave since records began in 1901. It is also the ninth time since 1901 that Belgium has experienced two or more heatwaves in a single year, and the sixth such occurrence this century. The year with the most heatwaves remains 1947, which saw four.
The first heatwave of 2026 ran from June 17 to June 28, as Meteovista reported at the time. A very warm period in mid-July came close to meeting heatwave criteria but fell short by one tropical day.
Heat Warnings and Thunderstorm Risk
On Monday, August 3, the KMI issued code orange for heat across almost all of Belgium, except West and East Flanders and the coast, with temperatures reaching up to 36°C inland. The Redactie24 reported that authorities sent a BE-Alert warning to citizens, noting that the heat could pose health risks, particularly for the elderly, young children, pregnant women, and those with chronic conditions.
Code yellow for heat remains in effect until Wednesday, August 5, except at the coast. From Wednesday, temperatures are expected to drop to 24-28°C, likely ending the heatwave after nine days.
There is also a chance of thunderstorms on Monday and Tuesday, especially in the southeast. According to NoodweerBenelux, some storms could be severe, with wind gusts potentially reaching 70-100 km/h in localized areas. The weather service noted that the Ardennes and southeastern regions face the highest risk of intense thunderstorms.
Drought Deepens Across the Country
The heatwave has been accompanied by significant drought conditions across Belgium. Code orange for drought has been in effect in Flanders since mid-July, with code red currently “not on the table,” according to the Flemish Drought Commission, which will meet again on August 13.
The drought has severely impacted agriculture. As VRT NWS reported, potato harvests in the Westhoek are expected to fall far below normal, with buffer basins nearly empty. Farmers are struggling to find water for irrigation, with some paying up to €10 per cubic meter for transported water. “We’re in trouble,” said Danny Metsu, a farmer and alderman in Ieper, describing the situation on his dried-out potato field.
Philip Fleurbaey, owner of a farm shop in Ieper, summed up the mood: “I too want long, thick fries on my plate: they are the pride of our Belgian land, but unfortunately 2026 will not be a great fry year.”
The drought has also triggered blue-green algae blooms in multiple locations across Flanders. The beach zone at Sport Vlaanderen in Hofstade has been closed due to the presence of cyanobacteria, and the Schelde in Ghent has turned bright green. As Weer.nl explained, warm, stagnant water creates ideal conditions for these potentially toxic bacteria to multiply.
Inland Shipping Under Pressure
Low water levels are also affecting inland shipping. Ships on some waterways must leave 10-20% of their cargo behind. Philippe Govers of Koepel Binnenvaart Vlaanderen warned that if no rain falls in the next two to three weeks, locks may need to be closed, forcing ships to leave even more cargo behind.
The situation extends beyond Belgium’s borders. The Rijn river in the Netherlands reached its lowest level ever measured (6.47m at Lobith), and the Danube is at record low levels, affecting nuclear power plants in Hungary and Romania. NoodweerBenelux’s forecast indicates that while temperatures will cool from Wednesday, significant rainfall remains unlikely in the near term.
What to Watch For
The Flemish Drought Commission is scheduled to meet again on August 13 to assess the situation. As Meteovista’s August outlook notes, the second half of August may bring slightly wetter conditions, though dry periods with regular sunshine are expected to continue dominating.
For now, Belgians can expect a brief reprieve from the extreme heat as temperatures return to more seasonal levels. But with drought conditions persisting and the possibility of severe thunderstorms on the horizon, the coming weeks will be critical for water management, agriculture, and public health across the country.