Wednesday will begin cloudy across much of Belgium before sunshine spreads nationwide in the afternoon, with temperatures reaching between 5C and 10C, according to the Royal Meteorological Institute (RMI).
Low clouds will cover most regions in the morning, although some areas may already enjoy sunny spells.
As the afternoon progresses, skies are expected to clear, bringing sunshine to the entire country.
However, moderate to occasionally fairly strong easterly to north-easterly winds will make conditions feel colder than the temperatures suggest.
On Wednesday evening and overnight, skies will become partly cloudy to clear, with minimum temperatures ranging from -1C to 4C.
Light ground frost is possible in some areas, including parts of low-lying Belgium. Winds will remain moderate in Flanders and along the Ardennes ridges, and light to moderate elsewhere.
Thursday is expected to be sunny across the country, with temperatures climbing to between 7C and 11C.
Winds will generally be light, occasionally moderate in northern areas and over the Ardennes high ground. Along the coast, moderate easterly winds will persist.
Cool conditions will continue into Friday, with temperatures hovering around or just above freezing in most regions early in the morning.
During the afternoon, temperatures are forecast to reach between 7C and 10C, potentially rising to 11C in eastern Belgium.
