Findel hits 36.3°C, Luxembourg's hottest June day on record, as heatwave grips Europe

Luxembourg recorded its hottest June day in nearly eight decades on Thursday, as a punishing heatwave tightened its grip on the Grand Duchy and much of Western Europe. The national weather service, MeteoLux, said the mercury reached 36.3°C at Findel on 25 June, a new June record for the airport station, where continuous observations began in 1947.

The reading edged past the previous June high of 35.4°C, set on 22 June 2017, and confirmed Luxembourg's place in a continental event that has toppled records from the Atlantic coast of France to southern England. It came during a red "vigilance" alert that authorities first raised at midday on Monday 22 June — coinciding with National Day celebrations — and later extended into the weekend.

A new mark at Findel

MeteoLux attributed the heat to a stubborn high-pressure system parked over central Europe, drawing in very hot air with little overnight relief and almost no rain. Forecasters warned the peak was not yet past, projecting temperatures of up to 40°C on Saturday before rain and cooler Atlantic air bring respite from Sunday, with daytime highs expected to slip back below 30°C the following week.

Thursday's record still falls short of Luxembourg's absolute all-time national high, set during the July 2019 heatwave. But the trajectory of June extremes is unmistakable: the 2017 record had itself replaced a 34.3°C mark from June 1947, and Thursday's reading lifted the bar again within a decade. Each step has come in a warmer baseline climate.

Records tumble across the continent

Luxembourg's milestone is one of many. France recorded its hottest day on record this week, with a national average temperature of 30.0°C on 24 June, surpassing marks set in July 2019 and August 2003; the town of Pissos, in the south-west, hit 44.3°C on 23 June. Roughly three-quarters of the country was placed under a red heat alert, hundreds of schools were closed and several nuclear reactors curtailed output as rivers used for cooling warmed. French authorities have linked dozens of deaths to the heat and to drownings during the hot spell.

In the United Kingdom, the heatwave produced the country's hottest June day on record — 36.4°C at Yeovilton, in Somerset, on Thursday, a day after 36.1°C was logged at Gosport in Hampshire. It was only the second time in British history that a red heat alert has been issued. Switzerland saw Basel reach 38°C, beating a long-standing record, while in Germany the national rail operator Deutsche Bahn offered free cancellations and advised passengers against travelling because of heat, wildfire and storm risks.

Scientists say such clustering of records is the signature of a warming world. Europe is the fastest-warming continent on Earth, heating at about twice the global average since the 1980s, according to the EU's Copernicus Climate Change Service.

Climate change is making heatwaves more frequent, more intense, and impacting larger geographical areas.

That assessment came from Samantha Burgess, Strategic Lead for Climate at the European Centre for Medium-Range Weather Forecasts, which runs the Copernicus service.

Luxembourg on alert

At home, the response has been coordinated from the National Crisis Centre in Senningen, where a joint operational command was activated bringing together the Grand Ducal Fire and Rescue Corps (CGDIS), the police, the Health Directorate, the City of Luxembourg, the army, the High Commission for National Protection and MeteoLux.

The Health Directorate urged residents — and especially the elderly, infants, isolated people and those with chronic illnesses — to take the heat seriously. Its guidance includes:

• Stay in cool or air-conditioned spaces and avoid the outdoors between 11:00 and 21:00.
• Drink plenty of water regularly throughout the day (at least 1.5 litres of water per day).
• Keep blinds closed during the day and open windows at night.
• Wear light clothing, cover the head outdoors and avoid alcohol.
• Cool the body several times a day, and check on vulnerable relatives and neighbours.

Hospitals and care homes were placed on high alert with enhanced staffing, while on-call medical centres and the 112 emergency line remained the first points of contact for those falling ill.

Protecting the most exposed

For people with nowhere cool to retreat, the strain is sharpest. The Luxembourg Red Cross, which runs the country's emergency shelter services, keeps its Nightshelter open from 19:00 to 09:00 and its daytime Bistrot Social "Am Haff" available for rest, meals, showers and sanitary facilities — part of a standing heatwave plan aimed at homeless and precariously housed residents.

The heat has also bitten into infrastructure. A heat-related fault on the track at Berchem, south of the capital, on Monday 22 June caused major disruption on the Luxembourg–Esch-sur-Alzette–Rodange and Luxembourg–Thionville–Metz lines, sharply cutting the number of trains. Repairs could only be carried out overnight, when temperatures fell far enough to work safely. The national operator, CFL, said the disruptions would persist until midday on Thursday 25 June, urging travellers to use the drinking-water fountains at Luxembourg station in the meantime.

With relief still days away when the record fell, officials stressed that the danger lies not only in the peak figure but in its persistence — successive hot days and warm nights that allow neither bodies nor buildings to cool. For Luxembourg, Thursday's 36.3°C was both a number on a chart and a warning about the summers to come.