May 1 was the warmest day this year; Temps to cool off from Saturday
The Netherlands experienced its warmest day of 2025 so far on Thursday, as temperatures surged across the country, reaching nearly 30 degrees in some areas. According to KNMI, the highest temperature was recorded in Westdorpe, Zeeuws-Vlaanderen, at 29.5 degrees.
In De Bilt, the national reference station, the maximum reached 27.4 degrees, marking the second official summer day of the year. The first occurred just a day earlier. Across most of the country, the weather was summery, with only the Wadden Islands staying below 25 degrees. Even there, conditions were unusually warm for early May, when typical temperatures range between 14 and 18 degrees, according to weeronline.
The warm conditions are the result of a prolonged stretch of sunshine and dry weather that has characterized the past week. With the ongoing May holiday, many residents took advantage of the rare combination of heat and clear skies to spend time outdoors.
Though the heat came close to triggering the first tropical day of the year—defined as temperatures of 30 degrees or higher—no official record was broken. The earliest tropical day ever recorded in the Netherlands remains April 21, 1968, when Venlo reached 32.2 degrees and Buchten in Limburg recorded 31.7 degrees.
The date-specific record for May 1 in De Bilt also remains unbroken. That record, set in 2005, stands at 28.5 degrees, with even higher values of 30.0 degrees in Eindhoven and Ell that same day.
Forecasters say a national heat record could still be broken on Friday, particularly in the central and southern regions. Inland areas may see temperatures between 25 and 28 degrees. The existing May 2 record in De Bilt is 26.3 degrees, set in 1990. The national record for all weather stations on that date is 27.5 degrees, registered in Twente and Soesterberg in 1966. According to meteorologists, this record may fall on Friday.
However, in the northern provinces, the weather is expected to be markedly cooler due to a shift in wind direction. A northerly breeze coming in over the North Sea will limit temperatures there to between 17 and 20 degrees. This signals the beginning of a gradual nationwide cooldown expected to continue into the weekend.
While Friday may still feel summery in southern regions, the weekend will bring increasing cloud cover and showers. Thunderstorms could develop late Friday, especially in the south. On Saturday, southern parts of the country are likely to see rain, with temperatures dropping to around 17 degrees.
Sunday, which is National Remembrance Day in the Netherlands, is forecast to be significantly cooler. The day will be mostly cloudy with occasional rain and a high of just 12 degrees. During the commemorations at Dam Square in Amsterdam in the evening, temperatures will likely be around 9 degrees.
Bevrijdingsdag (Liberation Day), celebrated on Monday, will remain cool and unsettled. While some sunshine is expected between the clouds, there is still no guarantee of a fully dry day. Temperatures will rise slightly to around 15 degrees.
Unusually warm sea temperatures and calm weather conditions have also led to the appearance of zeevonk, or sea sparkle, along the Dutch coast. The bioluminescent algae were visible Wednesday night on Terschelling, and warm evening temperatures on Thursday raised the chance of further sightings.
Zeevonk is a type of algae that thrives in warm, sunny conditions with little wind. When disturbed by waves or movement in the water, the organisms emit blue light due to a chemical reaction.
The current warm spell follows a particularly sunny and dry April. Meteorologists confirmed that April 2025 was the third-sunniest ever recorded in the Netherlands. The early May warmth is a direct continuation of that pattern, though it will soon give way to cooler, cloudier conditions.
