The Five Sunniest Julys

Here is a number that should ruin your morning coffee: the five sunniest Julys ever recorded in Luxembourg have all happened since 2005 [1]. Not spread across the last century. Not scattered through the record books. All five, crammed into the last twenty years.

MeteoLux published their July summary on August 5, and it confirms what anyone sweating through the last six weeks already suspected. June 2026 was the warmest June since records began in 1947, with an average temperature of 19.9 degrees. July then came along and made the point even harder.

361 hours of sunshine

Last month was the second sunniest July on record for Luxembourg, with almost 361 hours of sunshine. The only July that beat it was 2022, which saw 377 hours [2]. So the two sunniest Julys in 79 years of measurement are four years apart.

The driver was a persistent high-pressure system over Western and Central Europe, often reaching all the way from the Azores. Even when the pressure dipped, stability at altitude meant air masses dried out and warmed up. Clouds broke apart instead of forming. Rainfall stayed away.

150 litres instead of 280

Since April, Findel (Luxembourg's main weather station) has recorded only 150 litres of rainfall per square metre. The normal figure for that period is between 270 and 280 litres [3]. That is roughly half. The grass knows. The trees know. The farmers definitely know.

The average temperature at Findel in July was 21.2 degrees, more than two degrees above the reference average. Two degrees sounds small until you remember that "average temperature" smooths over everything. It means the cold nights were not that cold and the hot days were genuinely brutal. The heatwaves that rolled through southern Europe and sparked wildfires across the continent were not an anomaly. They were the trend arriving on schedule.

The trend is not subtle

A MeteoLux meteorologist, in an interview with RTL, pointed out that looking at the last 20 to 30 years of data, there is a definitive trend of summers getting warmer. And not just summers: all four seasons are shifting [4]. This can already be attributed to climate change, he said. The likelihood of summers like the current one will keep climbing as the climate continues to shift.

Not every summer will be an exceptional one. That is the thing about trends: they describe the direction, not every single data point. But the direction is clear, and Luxembourg will increasingly have to prepare for extreme events like heatwaves and prolonged drought.

What this means in practice

Luxembourg is not facing Mediterranean-style wildfires, at least not yet. But the country is already dealing with the consequences. The Moselle river is at record lows, forcing the Cattenom nuclear plant across the border to shut down three of its four reactors because there is not enough cooling water. Drought alerts are active across the region. Watering restrictions are in place in several municipalities.

The MeteoLux data is not a surprise. It is a confirmation. The climate models predicted this, and the measurements are arriving right on schedule. The question is not whether this will continue. The question is what adaptation looks like for a small country that imports most of its electricity, depends on rivers that are drying up, and has been averaging one "hottest ever" record per summer for the last few years.

The five sunniest Julys, all since 2005. The warmest June, this year. The second sunniest July, this year. Half the normal rainfall since April. At some point, you stop calling these events and start calling them the new baseline. We may already be there.