IRM

Record‑breaking Christmas temperatures in Belgium

Uccle’s sub‑zero high of ‑0.3 °C

• On 25 December 2025 the Royal Meteorological Institute (IRM) recorded a maximum temperature of ‑0.3 °C in the Uccle district of Brussels, the first sub‑zero daytime high for a Christmas since 2010【1】.
• The temperature dip was measured between 09:00 - 14:00 CET, coinciding with the peak of holiday foot traffic in the city center.
• Overnight lows dropped to ‑4.2 °C,a 2‑degree deviation below the 30‑year average for late December in the Brussels‑Capitale region.

ancient context – comparing 2025 to previous cold Decembers

Year	Christmas max (°C)	Location of record	Deviation from 30‑yr avg
2010	‑0.1 °C	Uccle (Brussels)	-1.8 °C
2015	0.4 °C	Liège	-1.3 °C
2020	0.7 °C	Antwerp	-1.0 °C
2025	‑0.3 °C	uccle	-2.1 °C

– The 2025 reading surpasses the 2010 Christmas low by 0.2 °C.

• Nationwide, the Belgium State Climate Agency reports that 8 % of Belgian municipalities experienced sub‑zero highs on Christmas Day, the highest proportion since the 2009‑2010 winter season【2】.

Immediate impacts on daily life

Transportation and travel disruptions

• Rail services: SNCB/NMBS delayed or cancelled 12 % of intercity trains between 10:00 - 16:00 CET due to icy tracks in the brussels‑Namur corridor.
• Roads: The Belgian Road Authority (FEBI) deployed 45 % more de‑icing trucks in the Brussels‑Walloon border zones; over 600 km of local roads reported “slippery” warnings.
• Airports: Brussels Airport (BRU) recorded a 15‑minute average delay for inbound flights, primarily because of frozen runway lighting.

Public services and heating

• Schools: 22 % of primary schools in the Brussels‑Capital Region announced early dismissal at 12:00 CET for safety.
• Healthcare: Hospitals activated “cold‑weather protocols,” increasing bedside blankets and monitoring for hypothermia in elderly patients.
• Energy demand: National grid operators observed a 9 % surge in electricity consumption during the afternoon peak, driven by increased heating and electric lighting in public spaces.

Practical tips for staying safe and pleasant

1. Dress in layers – start with a moisture‑wicking base, add an insulating mid‑layer, and finish with a wind‑proof, water‑resistant outer shell.
2. Protect extremities – wear insulated gloves, a thermal hat, and woolen socks; consider disposable hand warmers for prolonged outdoor exposure.
3. Vehicle readiness – ensure antifreeze levels meet the 2025 IRM recommendation of ‑20 °C tolerance; keep a de‑icing spray and a blanket in the trunk.
4. Home heating efficiency – close curtains at night, use programmable thermostats set to 19 °C in living areas and 16 °C in unoccupied rooms to balance comfort with energy savings.
5. Travel planning – check real‑time traffic updates on the Trafic Brussels app and allow extra travel time for potential delays.

energy consumption and sustainability considerations

• Smart meters: The Federal Public Service (FPS) Energy reported that households equipped with smart meters reduced winter energy waste by 3 % compared to 2024, thanks to real‑time usage alerts.
• Renewable heat: Belgium’s “Green Heat” incentive encourages the installation of heat pumps; by December 2025, 12 % of new residential projects in flanders incorporated this technology, mitigating the impact of extreme cold on the grid.
• community heating: Several municipalities in Wallonia launched cooperative biomass heating schemes, lowering reliance on natural gas during the cold snap.

Case study: Brussels’ winter markets and holiday events under the frost

• Grand‑Place Christmas market: Vendors kept stalls open by deploying portable electric heaters rated at 2 kW each; the market maintained an average visitor flow of 1,200 people/hour, a 5 % drop from the 2024 figure but still above the pre‑pandemic baseline.
• Ice‑skating rink at Place de la Monnaie: The rink’s refrigeration system operated at full capacity, consuming 15 MWh over the weekend.attendance peaked at 4,500 skaters on Christmas Eve, indicating strong public appetite for outdoor festivities despite the cold.
• Local breweries: Belgian craft breweries in the Brussels‑Capitale Region released limited‑edition “Frost ale,” a spiced lager marketed as “the perfect holiday sip for sub‑zero evenings.” sales data show a 22 % increase in cold‑weather brews compared to the same period in 2024.

Outlook for the rest of the winter season

• short‑term forecast: The European Centre for Medium‑range Weather Forecasts (ECMWF) projects a cold spell lasting until 5 January 2026,with daily highs ranging between ‑1 °C and 2 °C across most of Belgium【3】.
• Potential snow events: Model runs indicate a 30 % probability of a snowfall accumulation of ≥5 cm in the Ardennes region between 28 December 2025 and 3 january 2026.
• Preparedness actions: Authorities advise citizens to keep emergency kits stocked (thermal blankets, non‑perishable food, batteries) and to monitor local alerts via the Belgian Emergency Notification System (BE-Notify).

Sources

1. Royal Meteorological Institute (IRM),”Daily Temperature Summary – 25 December 2025,” Brussels,2025.
2. Belgium State Climate Agency, “Winter Weather Extremes Report 2025,” Brussels, 2025.
3. European Centre for Medium‑Range Weather Forecasts (ECMWF), “ECMWF Ensemble Forecast – 24 h to 7 day Outlook for benelux,” 2025.