Feels like Temperature

Have you ever noticed the term Feels like Temperature in your wether forecast page.

What is the difference between the max min and feels like temperatures. Why are these numbers sometimes so different? How do meteorologists know what the temperature will feel like to you?

How to calculate the ‘feels like’ temperature?

Although numeric, temperatures are not universal. Most of us have a sense of what a temperature of 75 degrees Fahrenheit means, but add a brisk wind and you will feel colder. Raise the humidity and the temperature your body experiences feels a lot higher too. Precipitation and cloud cover also play a role in making that 75 degrees a more relative experience. So how are “feels like” temperatures calculated?

Feels like temperature is calculated by taking into account the expected air temperature, relative humidity and the strength of the wind at around 5 feet (the typical height of an human face) combined with our understanding of how heat is lost from the human body during cold and windy days.

On windy days the speed of moisture evaporation from our skin increases and serves to move heat away from our body making it feel colder than it actually is. The exception to this rule, however, is when higher temperatures are concerned. At higher temperatures, wind chill is considered far less significant. Instead humidity plays a greater role. When a human being perspires, the water in his or her sweat evaporates. This results in the cooling of the body as heat is carried away from it. When humidity is high, the rate of evaporation and cooling is reduced, resulting in it feeling hotter than it actually is.

Using these facts we use a formula to adjust the air temperature based on our understanding of wind chill at lower temperatures, heat index at higher temperatures and a combination of the two in between.

So to understand better, 85 degrees at 10% humidity, the temperature feels closer to 79 degrees, but at 90% humidity, it will feel closer to 100 degrees outside.