Apparent Temperature

More commonly referred to as the "feels like" temperature, the apparent temperature is the temperature that your body senses under particular weather conditions. This is usually different to the reported temperature (as measured in a white louvered screen) and depends on other weather parameters, such as humidity or wind speed. Wind Chill and Heat Index are the two apparent temperatures that people might be familiar with and are described below.

Wind Chill

A temperature that represents the "feels like" temperature of wind on exposed skin in terms of an equivalent temperature in calm conditions. Wind speed is the most important factor in calculating wind chill, but humidity and pressure are also sometimes included. The wind chill effect arises because as wind blows over the skin, it evaporates moisture, leading to a cooling effect.

Wind chill look-up table

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Heat Index

An index number used to describe how hot the weather feels to the average person, by combining the effect of heat and humidity. The Meteorological Service of Canada describes a heat index of at least 30 as causing "some discomfort", at least 40 causing "great discomfort" and above 45 as "dangerous". Heat stroke is imminent when the heat index hits 54.

Heat index look-up chart

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