Cold weather hunter Pieter Bliek measured a temperature of 0.46 degrees Celsius below freezing at the Schoorlse Duinen last Saturday on Sunday night. How is it possible that it was so cold, when we have such a very hot summer? NH weatherman Jan Visser explains.
All conditions were just right for Bliek’s cold measurement. “It cools down fastest in the dune pans”, Jan Visser begins his explanation. “It is important that there is no wind and that it is exceptionally dry.” The -0.46 degrees was measured 10 centimeters from the ground. “They also call it clog height.”
Meteorologists do not measure as standard at this point in the Schoorlse Duinen, but Bliek and his partner now have measuring instruments there for 14 months. “It is a unique measurement,” says the NH weatherman. “Because until now it was not documented, but it must have happened more often. They wanted to show that it can also get so cold in these hot days and they succeeded.”
Sand and drought
Sand can get very hot and, it turns out, very cold. According to Visser, that goes very quickly. “If you are on the beach on a sunny day in the summer, the sand sometimes hurts your feet. It also works the other way. Sand can cool down very strongly, which has to do with the (poor) insulation .”
In the night from Saturday to Sunday, the conditions for such a historically low reading were ideal. Drought also plays an important role in this. “There is hardly any moisture. That is important, because if there is water vapor in the air, it is at the expense of the cold. That is because that moisture retains the heat.”
Furthermore, there was little frost in the area, says the weeman. It only went below 0 in the dune pan. In the built-up area in Schoorl, the freezing point has not been reached. “It is really only possible in the dune pans,” he says.
Watch the video below in which Pieter Bliek explains more about the record.