▣ What Is “Perceived Temperature”?
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Perceived temperature refers to the temperature that people actually feel, which takes into account not only the air temperature but also factors such as wind and humidity.
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In other words, even if the air temperature is the same, stronger winds or higher humidity can make it feel colder or hotter. Perceived temperature expresses this difference as a measurable value.
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In summer, it is typically determined by considering both air temperature and humidity. Humidity plays a key role because when it is high, sweat evaporates less efficiently, reducing the body’s ability to release heat—thereby increasing the risk of heat-related illnesses.
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▣ Concept of Perceived Temperature
| Actual temperature | The air temperature measured with a thermometer. |
| Perceived temperature | The temperature felt by the human body, taking into account the effects of wind and humidity |
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▣ Calculating Perceived Temperature
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1) Summer perceived temperature – Calculated using air temperature and humidity (e.g., Heat Index)
2) Winter perceived temperature – Calculated using wind speed and air temperature (e.g., formulas used by Environment Canada)
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▣ Perceived Temperature and Health
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- High perceived temperature – Increases the risk of heatstroke, dehydration, and cardiovascular problems.
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Low perceived temperature – Increases the risk of frostbite and hypothermia..
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▣ Heat Index
The heat index is a measurement used to estimate how hot it feels by combining air temperature and humidity.
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▣ Factors Affecting Perceived Temperature
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1) Summer: Humidity
- When humidity is high, sweat evaporates less efficiently, making it feel hotter and more uncomfortable.
- Example: At 33 °C with humidity above 80%, the perceived temperature can exceed 40 °C.
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2) Winter: Wind
- Wind increases heat loss from the skin, making it feel colder.
- Example: Even if the air temperature is 0 °C, strong winds can make it feel like –10 °C or colder.
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