The weather will be generally dry and sunny during the early part of Sunday, but there is a risk of violent storms in the afternoon, with considerable amounts of rain, hail and strong gusts of wind in some areas, according to the Royal Meteorological Institute (RMI).
Otherwise, the wind will be slight or moderate.
Highs will range between 24 degrees in Hautes-Fagnes and 30 degrees in Kempen.
Stormy weather is expected to continue into Sunday evening, mainly in the east and north of the country, before shifting gradually towards the Netherlands and Germany on Sunday night. The weather will then become dry with broad swathes of clear sky and, in some areas, the formation of mist and fog banks.
Lows will vary between 12 degrees in Hautes-Fagnes and 17 degrees in the centre of the country. The wind will be slight to moderate.
Dry, sunny weather is expected on Monday morning, followed by changing skies and localised afternoon showers – possibly storms. The probability of rains will be highest along the coast and in the east of the country.
Highs will range from 21-22 degrees along the coast and on the Ardennes Heights to 26 degrees in Kempen. The wind will first be slight and then moderate.