Belgium under nationwide yellow thunderstorm warning from Thursday afternoon

Belgium’s Royal Meteorological Institute has placed the entire country under a yellow thunderstorm warning from 17:00 on Thursday, 27 August, until 04:00 on Friday, with intense rain, hail and strong wind gusts forecast locally.

Belgium Impulse Editorial·27 August 2026·3 min read·

Well established· 1 primary source + 3 official documents + 1 independent reporting source · Background sources: 1

TopicsBelgium thunderstorm warningIRMBrussels weather warningyellow warningBelgian weather27 August thunderstormsRoyal Meteorological Institute of Belgium

In 30 seconds

The warning runs from 17:00 Thursday to 04:00 Friday.
All Belgian provinces and Brussels are covered.
The IRM forecasts 20–40 l/m² of rain within one to six hours in several places.
Higher local totals, hail and strong wind gusts remain possible.

Updated 27 August 2026 — BELGIUM: The

() has placed every Belgian province and under a yellow thunderstorm warning from 17:00 on Thursday until 04:00 on Friday. The institute expects a storm system to enter Belgium from the south late in the afternoon, bringing locally severe thunderstorms and a risk of disruption.

The IRM forecasts rainfall totals of 20 to 40 litres per square metre within one to six hours in several places, with higher amounts possible in isolated locations. It says the storms can also produce hail and strong wind gusts. The precise path and intensity of individual cells remain uncertain because thunderstorms develop on a small geographical scale.

A yellow warning means vigilance is required. Under the IRM’s official system, that level is issued when hazardous weather has a sufficient probability of reaching defined thresholds within 48 hours. For thunderstorms, the yellow criteria include heavy rainfall, hailstones measuring one to two centimetres, strong gusts or dangerous lightning. The warning does not mean that every municipality will experience severe weather.

The alert follows an exceptionally warm and dry Belgian summer. In a seasonal assessment published this week, the IRM said summer 2026 was on course to become Belgium’s warmest since national records began in 1833. It also reported an unusually dry period between 1 July and 15 August. That background does not determine where Thursday’s storms will strike, but intense rain falling rapidly onto hard or dry ground can create local drainage and surface-water problems.

The weather system forms part of a wider unstable pattern affecting France and neighbouring areas. Météo-France reported successive storm outbreaks this week and expected an active storm zone to extend towards northern France on Thursday, consistent with the IRM’s forecast of storms entering Belgium from the south.

Where this is happening

View on map Royal Meteorological Institute of Belgium →

Royal Meteorological Institute of Belgium · 50.799, 4.358 · Open in OpenStreetMap ↗ · Source: Wikidata Q3152508

Residents should secure loose outdoor objects, avoid sheltering beneath trees and monitor the IRM’s warning map and radar. The National Crisis Centre advises people to follow official information during natural hazards. Travellers and event organisers should allow for sudden local disruption, while the IRM may revise the warning as observations clarify the storms’ route and strength.

Who’s affectedBrussels commuterspublic transport passengersdrivers across Belgiumoutdoor event attendeesevent organisersresidents in flood-prone areascyclists and pedestrians

Context & what happens next

What to do

If you are travelling, commuting or attending an outdoor event on Thursday evening, check the latest IRM warning and transport or organiser updates before leaving. Carry rain protection, allow extra journey time and avoid exposed outdoor locations during lightning or strong gusts. Secure loose items on balconies, terraces and gardens, and move vehicles or valuables away from places prone to local flooding where practical. The main period to watch is 17:00 on Thursday, 27 August, through 04:00 on Friday; conditions may vary sharply over short distances.

Impact

Regional — The warning applies to Flanders, Wallonia and Brussels. The storms are forecast to enter from the south, but the IRM has not identified any one Belgian region as certain to receive the strongest impacts.

Evidence

Well established · 1 primary source + 3 official documents + 1 independent reporting source · Background sources: 1

Explore evidence →

Royal Meteorological Institute of Belgium — national warnings