Why are the actual temperature and the 'feels like' temperature sometimes so different? How do meteorologists know what the temperature will feel like near you? Everyday Einstein explains.
What Is the Windchill Factor?
On the other end of the temperature spectrum is the windchill factor. Wind can cause sweat from our bodies to evaporate faster and can carry heat away from us quickly to make us feel colder. Thus, for example, a temperature of 75 degrees can feel more like 65 degrees with windspeeds of 60 miles per hour.
How Do You Estimate a 'Feels Like' Temperature?
When a weather service makes a prediction about what a temperature will feel like, they typically include these basic measurements of the heat index and the windchill factor. A more complex estimate comes from the metric established in the 1990s and patented by Accuweather called the RealFeel Temperature. Their model includes heat index and windchill, but also other weather factors like cloud cover or UV index, sun intensity, visibility, and ground cover. They further incorporate expected heat transfer rates across an average sized human body with an average metabolism. And they assume the person is dressed appropriately for the weather.
Ultimately, “feels like” temperatures are an effort at understanding and quantifying the human response to temperature, a relationship with multiple complicating factors. For starters, I can sit in a conference room in a scarf and sweater while my colleague next to me is comfortable in his t-shirt. Some of this difference comes down to our varying metabolisms—how fast we burn calories to produce heat and how fast that heat is dissipated over the surface area of our bodies. Our bodies may prefer different temperatures as well, like when a person is said to “run hot” or “run cold.”
So while there is still much estimation involved in determining “feels like” temperatures, they do a pretty good job of preparing us for what the weather has in store. And as we heard from meteorologist Morgan Miller in an earlier episode, local weather forecasters usually know what estimates work best for their region and can combine that knowledge with their personal experience to give you the best “feels like” estimate.
Until next time, this is Dr. Sabrina Stierwalt with Everyday Einstein’s Quick and Dirty Tips for helping you make sense of science. You can become a fan of Everyday Einstein on Facebook or follow me on Twitter, where I’m @QDTeinstein. If you have a question that you’d like to see on a future episode, send me an email at firstname.lastname@example.org.