If you are outdoors and cold, you take shelter from the wind as wind bad for skin. This action seems intuitive. On windy days you cannot always rely on the brand of the thermometer to choose how much shelter you will use when leaving home.
In addition to the air temperature, there are other meteorological variables that influence the cold that a person can feel.
On windy days you cannot always rely on the brand of the thermometer to choose how much shelter you will use when leaving home in cold wind and naked skin. In addition to the air temperature, there are other meteorological variables that influence the cold that a person can feel.
To quantify this temperature difference between what we feel and what the thermometer marks you use the “Thermal Sensation”. Its function is to give an idea of the degree of comfort that the body feels, or in other words, it expresses in a more reliable way the temperature we feel when being outdoors.
Why are you colder?
The heat of your body passes into the air that is in contact with the skin, a process known as conduction. When there is little wind, a small layer of air forms around us that receives heat and increases its temperature causing the loss of heat from the body to decrease.
The dangers of wind cooling
In some extreme conditions, hypothermia or freezing can arrive in a matter of a few minutes. With temperatures of 7 ° C below zero and winds of 60 km / h, the thermal sensation will be close to -17 ° C, that is 10 degrees less than if there were calm. And if the wind rises to 90 km / h, a very common situation in the high mountains, in just 2 hours we could begin to experience the symptoms of freezing.
This index – which you call thermal sensation – takes some considerations:
- Wind speed at 1.50 m high (average height of the human face)
- It is based on a model that takes into account the human face
- It incorporates the theory of heat transfer between the wind-chafed skin and the environment.
- Consider a person in motion with an average speed of around 5 km / h.
- It uses a typing of the resistance of human skin tissue.
It assumes the most unfavorable scenario in terms of solar radiation: at night and with clear skies, when the loss of heat to outer space is maximum.