It is already hot throughout most of the Netherlands but the Dutch national weather forecasting service KNMI predicts next week will be even warmer.

The temperature is already 24.7 degrees in De Bilt, where KNMI is located and the location the country uses to define tropical weather conditions. To be declared a tropical day, temperatures must top 30 degrees. Monday and Tuesday next week may see as high as 40 in parts of the country.

The weather institute warns that we could see a code yellow for heat, especially in the south. The high temperatures can lead to health problems, especially for the elderly and vulnerable populations.

The Vierdaagse – or four day march – sees some 50,000 people walking up to 220 kilometres over the course of four days and is set to begin on Tuesday. Organisers are already planning for the extreme heat.

March leader Henny Sackers told the AD they may start earlier or drop a day entirely if the temperatures are too dangerous. ‘We have a so-called extreme weather scenario ready,’ he said.