The Netherlands records hottest summer ever in 2026, says KNMI

After several heatwaves and stuffy nights, it is perhaps unsurprising that in 2026, the Netherlands has experienced its hottest summer since records began. 

Summer 2026 breaks records in the Netherlands  

Based on temperature data from the Royal Dutch Meteorological Institute (KNMI), the summer of 2026 was the hottest summer in the Netherlands since measurements began in 1901. The average temperature measured at the De Bilt weather station over the past three months was 19,3 degrees celsius.

This breaks the previous record of 18,9 degrees set in 2018, reports NOS. "We had the highest number of days above 35 degrees, the number of tropical days is higher than ever, never before have we had so many consecutive days with nighttime temperatures of 22 degrees or higher," KNMI climate expert Peter Siegmund told NOS. "And it all started in June, normally the least warm summer month. That really surprised me."

In June, temperatures soared to record highs, with KNMI issuing a code red for extreme heat for the first time ever. Since then, the country has been through several heatwaves, seen heat records broken and is currently experiencing a drought. 

Hot summers to become more frequent

According to Siegmund, the average summer temperatures over the past few years have been higher than KNMI’s highest climate scenario, which is based on climate predictions. The highest scenario involves rapidly increasing emissions, basically predicting the worst climate outcome, while the lowest scenario involves rapidly decreasing emissions to limit global warming, predicting a favourable outcome. 

KNMI has calculated that we can expect extreme summers like this to occur every five years, becoming more frequent over time. Based on current temperatures, the heat we experienced this summer will likely be the average for a summer in 2050, under the highest climate scenario.

"In the high scenario, the temperature continues to rise at about the same rate until the end of this century as in the past 30 years," explained Siegmund. "In the low scenario, it continues to rise until 2050 and then remains stable. Around 2050, it makes about a degree difference whether you are in the high or low scenario. In 2100, that difference is 4 degrees. So that is a lot." Climate policy can still make a difference in the coming century, Siegmund emphasises. 

Whether the coming autumn will be an extreme one remains to be seen. Over the past century, Dutch autumns have become warmer and wetter, and with how warm the sea currently is, the Netherlands could be hit by some heavy showers in the coming season.