Belgium Set for Sunny Week as Temperatures Climb to 25°C
After a cloudy start to the week, Belgium is poised to enjoy a spell of warm, sunny weather that will see temperatures rise steadily from Tuesday onward, with the potential for tropical heat by the end of the week. According to VRT NWS, the Royal Meteorological Institute (KMI) forecasts a transition from Monday’s mix of clouds and sunshine—with maxima between 16 and 21°C—to increasingly bright and warm conditions.
Day-by-Day Forecast
Tuesday (June 16) will bring morning clouds and a chance of local showers, clearing to dry and sunny conditions by the afternoon. The KMI expects maxima ranging from 19°C at the coast to 25°C in the far south and the Kempen region, as reported by VRT NWS.
Wednesday (June 17) will be sunny south of the Sambre and Meuse rivers, with a mix of clouds and sunshine in the north. Clearing is expected everywhere by evening, with temperatures between 22°C at the coast and in the High Ardennes and 26°C elsewhere.
Thursday (June 18) is forecast to be mostly sunny, with inland maxima climbing to between 27 and 31°C. Coastal areas may experience fog and a moderate sea breeze, keeping temperatures around 22°C.
Friday (June 19) will see unstable air moving in from France, bringing variable cloudiness and a chance of thunderstorms from the morning. The day will be muggy and very warm, with maxima reaching 29 to 33°C.
The weekend (June 20-21) looks set to remain warm, with Saturday forecast at 29°C (40% rain chance) and Sunday at 30°C (10% rain chance), according to KMI data.
Summer 2026 Outlook: Warmer Than Average
Beyond the immediate forecast, seasonal models are converging on a significant prediction: Belgium’s summer of 2026 is likely to be warmer than average. As HLN science expert Martijn Peters reported, three major seasonal models all point to above-normal temperatures.
The American CFS model predicts anomalies of +0.5 to 1°C, while the European SEAS5 model—considered one of the world’s best—goes further, forecasting deviations of up to 1 to 2°C. The Copernicus C3S multi-model ensemble, which combines forecasts from eight institutions, also projects a warmer-than-average summer with anomalies of +0.5 to 1°C.
Rico Schröder, meteorologist at Meteovista, noted that “the seasonal models show very clear signals for a warm and fairly dry summer. All maps show warmer weather than usual in June, July and August.”
Climate Context: A Warming Trend
The forecast fits within a broader pattern of rising temperatures in Belgium. According to KMI data cited by HLN, the number of summer days (temperatures of 25°C or higher) has risen from an average of 20.4 per year in the 1961-1990 period to 29.9 per year in the 1991-2020 period. Tropical days (30°C or higher) have more than doubled, from 2.3 to 5.3 per year.
Heatwaves are also becoming more frequent and longer-lasting, increasing by 0.3 per decade since 1981 and lasting two days longer per decade. The highest maximum temperature recorded in Ukkel has been rising by 0.85°C per decade, with the all-time record of 39.7°C set on July 25, 2019.
What to Watch For
The convergence of multiple seasonal models pointing to a warmer summer, combined with a dry spring that has left soils parched, raises the risk of heatwaves and potential drought conditions in the early-to-mid summer period. As Meteovista’s analysis notes, dry soil amplifies heat: less moisture means less evaporation, more solar energy goes into heating the air, and fewer clouds form.
For now, Belgians can look forward to a pleasant week ahead—with the sunscreen and thunderstorm umbrella both likely to be needed before the week is out.