Why the same air temperature can feel so different to many of us
Actual air temperatures are measured with finely calibrated instruments, but our bodies are more subjective and uncalibrated. So, the same temperature can feel very different to us depending on location, wind and humidity.
Let's start with "location, location, location." Fifty degrees Fahrenheit may feel warm to someone in International Falls, Minnesota, while that same temperature leaves residents of Tampa, Florida, feeling quite cold.
In both places, people have become acclimated to the weather in their location, creating the physical perception of a huge temperature difference despite the fact that it was the same 50-degree reading.
Just last month, an extreme Arctic outbreak slid south across the lower 48 states with temperatures running 20 to 40 degrees below average.
International Falls, Minnesota, reached a low of -34 degrees with wind chills to -42 degrees. In Sioux Falls, South Dakota, it dipped to -14 degrees, and in Kansas City, Missouri, temperatures bottomed out at -9 degrees. Even farther south, Amarillo, Texas, touched 4 degrees, and even Tampa felt the big chill at 34 degrees.
Here in Philadelphia, we hit a low of 10 degrees with wind chills to -11 degrees.
You can bet folks in Minnesota would have welcomed our 10 degrees or Tampa's 34 degrees as a pleasant warm-up. The opposite was true in Tampa, where 34 degrees was incredibly cold, leaving residents in heavy winter parkas.
Humidity can also make a big difference. Here in Philadelphia, a humid 60-degree day will create a heat index that feels more like a 65-degree day because the higher humidity saturates the air and prevents evaporative cooling from our skin, leaving us warmer and sweatier.
If we add wind on a humid day, it can also make a difference by cooling us so that we feel like the actual temperature is 60 degrees.
Similarly, if we add that same wind on a dry 60-degree day, it has a cooling effect or wind chill and can make us feel more like 55 degrees.
There is also a psychological component to why the same temperature is perceived to feel so different. Just the image of sitting in ice water can make you feel cooler on a 60-degree day. On the flip side, the image of sitting in a hot sauna can make you feel hotter on a 60-degree day.
Meteorological spring begins Saturday, bringing a transition from the cold season of winter to the hot season of summer.
Here in the Delaware Valley, we will start feeling differences at the same air temperature.
It is the time of year when a warm coat may be needed on a 60-degree day that is dry and windy. While several days later, just a T-shirt feels great on a humid, less windy 60-degree day.