June 2026 will go down in history as a landmark month in Luxembourg. With an average temperature of 19.9°C, it narrowly surpassed the previous peaks of 2003 and 2023, which both stood at 19.8°C.
Compared to the 1991–2020 climatological norm of 16.7°C, the difference reached 3.2°C – an exceptional anomaly for an early summer month.
The month's weather patterns were marked by a dramatic progression. The first 10 days were surprisingly cool, averaging 13.9°C, which is 2.2°C below the norm.
Temperatures then rose sharply between 11 and 20 June, reaching an average of 19°C, before soaring into extreme heat during the final 10 days.
From 21 to 30 June, the average climbed to 26.7°C – a deviation of 9°C from usual values. Maximum temperatures hovered around 33.3°C, while minimums stood at approximately 20.1°C, levels characteristic of a major heatwave.
It was this scorching end to the month that pushed June 2026 into the record books. The Findel weather station recorded eleven consecutive days of heat, with maximums exceeding 30°C, including six tropical nights during which the temperature never dropped below 20°C.
On 26 June, a new all-time record for the month of June was set at 38.2°C.
The heat was accompanied by a rainfall deficit: 59.5 litres per square metre were recorded, compared to a norm of 73 litres per square metre. Sunshine was also abundant, with 263.3 hours of sunshine recorded – roughly 22 hours more than the average.
With this new record, June 2026 now tops the list of the hottest Junes ever measured at Findel, ahead of 2003, 2023, 2019, and 1976. The month marks a new milestone in the series of heat events that have increasingly come to characterise the start of summer in Luxembourg.
