What is the perceived temperature?
Weather conditions have a huge impact on the way we hike. The right clothing can prepare you for the weather: sun, rain, snow or wind. They have a significant effect on the temperature our bodies feel during exercise and when we stop. In this article, we explain what temperature feels like and how to understand it when hiking.
Definition of core body temperature
Feeling temperature is an indicator used to prevent extreme cold or heat waves. It takes into account the measured temperature, the wind speed and the ambient humidity. The Futura Sciences article explains the difference between perceived temperature and ambient temperature (which is measured under shelter from wind, sun and precipitation).
The first index of perceived temperature is the Wind Chill effect. It corresponds to the feeling of cold produced by the wind for a given ambient air temperature. In simple terms, the body expends energy to create a film of warm air on the surface of the skin. When there is wind, this film is blown away, the skin comes into direct contact with the wind and a sensation of cold is produced. So the temperature you feel is the cold feeling you will get when hiking in the wind.
Another index similar to wind chill is the Humidex factor. It was created to measure the risk to the human body from excessive heat and humidity. Humidity makes the evaporation of your sweat less efficient and the risk of discomfort increases.
Calculation of the perceived temperature
Wind chill is calculated between +10 °C and -50 °C. The table below shows the wind chill for a given temperature and wind speed. This data can vary from person to person, as the temperature felt is different for different ages, fitness levels and body sizes. On the table, the darker the results are displayed, the higher the risk of frostbite.
By studying the table, we can conclude that :
The higher the wind speed, the colder it feels.
The colder it is, the more influence the wind has.
Even a light wind will change the body temperature.
The Humidex factor is based on the ambient temperature, vapour pressure and dew point. It is a unitless index that indicates the risk of hot weather. It ranges from less than 30 (no discomfort) to more than 54 (heat stroke is imminent).
Prevention against the temperature felt
In France, conditions are not as harsh as in North America where the Wind Chill effect and the Humidex index are widely used. It is still important to be aware of the weather if you are going to be hiking.
Take appropriate clothing, cover your skin, protect the extremities of your body, especially your head (a windproof hood will prevent heat loss). Keep yourself well hydrated and remember to take shelter with the natural elements when you take a break or set up camp.
The weather should not be underestimated when hiking or doing any other outdoor activity. It is therefore important to take into account the temperature felt in order to equip yourself accordingly and to take certain preventive measures to avoid suffering from the cold or heat.