CHARLOTTE, N.C. — One of the most common questions WCNC Charlotte's meteorologists are asked is why it feels so much hotter than their weather app or even the thermometer at home indicates.
You may have heard temperature readings are taken in the shade so you have to factor in the humidity or solar radiation based on where you are, but that statement is only half true.
Temperature is not technically measured in the shade.
In Charlotte, our measurement comes from the airport by an ASOS (Automated Surface Observing System) unit.
This is the official data that goes into the weather record books each day.
The temperature portion of the ASOS is shielded in a well-ventilated area with direct sunlight. So, it’s shielded from the sun’s radiation, not shaded from it.
It pulls in the surrounding air inside using a fan, and there's a probe inside that takes temperature readings.
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Chris Horne, the Observing Program Leader at the National Weather Service in Greenville-Spartanburg, said having a standard for how they measure temperature gives everyone the same starting point.
"You're probably going to get too wild of a swing, having exposed probes, fully exposed to radiation throughout the day," Horne said.
Many of the temperature measurements the National Weather Service takes across the country are read by ASOS units.
There are special parameters taken, too, which are dictated by the World Meteorological Organization and the NWS. They follow these rules to ensure accuracy.
"You're supposed to be about five feet above ground level," Horne said. "It has to be in a representative area of what you're sampling. For example, you want to keep it out of a drainage ditch, make sure it's far enough from any kind of artificial surface, such as a parking lot or the taxiway of an airport."
This also allows other factors to be taken out of the equation, such as humidity and solar radiation.
While we can debunk that temperature readings are taken in the shade, the number you see on your WCNC Charlotte news app is pulled from the airport, just like the official data.
This means in the direct sunlight or increased humidity -- especially for hours at a time -- you will feel hotter. This is why breaks in the shade and staying hydrated is vitally important when the temperatures are high.
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