Featured Image for Techly Explains: How is the ‘feels like’ temperature calculated?

Techly Explains: How is the ‘feels like’ temperature calculated?

Sometimes the temperature is not the temperature.

In 2005, the Australian Bureau of Meteorology (BOM) rolled out the use of “feels like” as a way of measuring temperature.

“Feels like” doesn’t sound very scientific, but BOM and other weather agencies will tell you it’s a legit thing.

At the risk of stating the obvious, “feels like” is a term that BOM uses to describe what the outdoor air feels like apart from the actual temperature. BOM says that by checking both figures, you should be able to decide better what to do with your day.

For example, it’s a pretty miserable 18 degrees in Adelaide at the time of writing. But the “feels like” temperature is actually much lower at 12 degrees. This tells me I shouldn’t leave the house and had better binge watch something. Thanks, BOM!

According to BOM’s Weather Words glossary, “feels like” is “a measure of the discomfort caused to an appropriately dressed adult, walking outdoors, in the shade, by the current wind and humidity levels.”

So how is it calculated? Does a meteorologist walk in the shade outside (clothed)? Or just stick an arm out the window (gloved)?

The answer to these questions is that BOM applies a mathematical model to data from thermometers sheltered from sun and wind.

The model is called “The Steadman Apparent Temperature”. It was invented by Dr Robert Steadman and it takes into account things such as wind chill and humidity in a particular location.

According to ABC Science, Steadman also modelled heat loss or gain we may experience from breathing, blood flow and sweating.

Wind chill strips our bodies of the cosy warm layer of air that surrounds us and makes it feel colder than it is. Conversely, humidity traps sweat on your body, making you feel hotter.

Because of this, you should probably check “feels like” when you are in places with extreme weather like Darwin or Melbourne’s alpine regions.

One thing the Steadman Apparent Temperature doesn’t take into account is direct sunlight. The model also assumes you are appropriately dressed, so if you are wearing a soaking wet t-shirt on a cold day, you are gonna have a bad time.

Going back to today’s example, it is currently 30 degrees in Darwin but feels like 34.

Meanwhile, at Mouth Hotham in Victoria, it’s 11 degrees but feels like 6. Ouch.

If you have any more weather-related questions, you can check out the official BOM YouTube channel.

About the author

Stefan is an Adelaide-based freelance writer. In his spare time, he plays tennis badly, collects vinyl and brushes up on his Mandarin. Follow Stefan on Twitter

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