Belgium weather: Cool, wet midweek with highs to 24C, weekend heat up to 28C, then storms Sunday
After a cloudy, rainy Wednesday and Thursday, Belgium will see a sunny warmup Friday and Saturday, with temperatures reaching 28C, before a thundery breakdown on Sunday.
Midweek cool and wet spell
Wednesday, July 22, will start with numerous cloud fields and occasional light rain, as per the IRM morning forecast. Highs will range from 18 degrees over the Hautes-Fagnes to 23 degrees in Belgian Lorraine, with a moderate north to northwest wind. In the evening, clearer spells will develop, but overnight new cloud will drift in from the north and some fog banks could form again in the Ardennes. Under the clouds, a few showers are possible, with widespread minima between 7 and 16 degrees and a light wind, except at the coast where it will remain moderate. Thursday will open under a heavy overcast with intermittent drizzle; low cloud will locally reduce visibility on the eastern high ground, under a light north-northwest wind. During the afternoon, conditions will become generally dry and the cloud cover will gradually thin, allowing more sunshine through, though a full clearance is not expected until late evening. Maximum temperatures on Thursday will be between 19 and 20 degrees on the Ardennes heights and the coast, and 23 or 24 degrees in the Campine region.
Weekend heat and sunshine
Friday will be sunny as the anticyclone re-establishes itself over the region, with highs reaching 24 or 25 degrees in the centre under a light north to northwest breeze. Saturday will see even more abundant sunshine, accompanied by some high cloud veils, and a sharp jump in temperatures: the centre will reach 28 degrees, the Ardennes 25 degrees, and the coast 23 degrees. The IRM warns of a growing risk of an isolated shower towards the end of the day on Saturday. This rapid return of summer heat follows the unsettled midweek period.
- Cloudy with light rain, highs 18–23 °C
- Morning drizzle and low clouds, afternoon clearing, highs 19–24 °C
- Sunny and dry, highs 24–25 °C
- Hot and sunny, up to 28 °C, risk of late shower
- Showers and thunderstorms, temperatures drop to 16–21 °C
- Residual showers possible, highs 19–21 °C
- Sunny with anticyclone, highs 22–26 °C
Thundery breakdown Sunday
On Sunday, a succession of small disturbed zones will cross the country, bringing showers and local thunder, as forecast by the IRM. The weather will undergo a sharp cooling, with maximum temperatures dropping to just 16 degrees on the Ardennes heights and 20 to 21 degrees in the centre. Widespread rain is expected, marking a sudden end to the brief heat spike.
Next week: short-lived instability then recovery
Monday will remain unsettled, with residual instability and a few showers possible, while temperatures stay relatively low at 19 to 21 degrees. On Tuesday, a new anticyclonic push will restore sunny and luminous conditions. Highs will bounce back to 22 degrees at the coast, 23 degrees in the Ardennes, and around 26 degrees elsewhere, according to the IRM outlook.
