So far this year the Netherlands had 51 summer days - days on which temperatures climbed to 25 degrees or higher in De Bilt, according to Weeronline. 2006 also had 51 summer days, but spread over the entire year.
Sunday was the 51st summer day of 2018. Only one more hot day is needed to break the 2006 record. This may happen on Wednesday or Thursday, when maximums of around 25 degrees are expected. Temperatures also often climb to above 25 degrees in late August and September, according to Weeronline. In 2006 the 51st summer day only happened on September 22nd.