It only freezes a few degrees, but the KNMI still gives code yellow for the east and southeast of our country due to the cold. Five questions and answers about the perceived temperature.
What is perceived temperature?
When the wind blows harder, it feels colder. We call that perceived temperature or windchill. The lower the perceived temperature, the faster we cool down (and the faster the water pipe freezes). Today, according to the KNMI, it can feel like -12 to -15 degrees.
Isn’t perceived temperature just an imagination?
No, it is a scientific measure. The KNMI determines the perceived temperature with the table below. At a perceived temperature of -15 degrees or lower, the service can issue a warning, such as code yellow today.
Why does the KNMI warn about a low perceived temperature?
A low perceived temperature is dangerous, because you can quickly suffer from frostbite. This certainly applies if you cycle or skate against the wind. Your own speed is then in addition to the wind speed. Many participants in the 1963 Elfstedentocht suffered from frostbite because they skated against the wind for a long time.
How is the perceived temperature calculated?
The KNMI uses the so-called JAG/TI method. That is a combination of air temperature and average wind speed. The perceived temperature calculated in this way applies to a healthy, adult, walking person of average height.
On February 7, 2012, Lelystad recorded the lowest perceived temperature in our country: -28.6 degrees!
Is there also a perceived temperature for heat?
Yes, warm weather feels warmer when there is no wind and high humidity. Our bodies cool down by evaporating sweat, but that evaporation stagnates if the surrounding air is too humid. A fan that blows away the moist air then provides cooling.