Do NOT Trust Apple’s Weather App For Wind Chill Information!

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When I was a kid, the concept of ‘wind chill’ was new; the National Weather Service didn’t start reporting it until the 1970s, and it took a while longer to become popular with news viewers. Now it has evolved into ‘Real Feel’ or ‘Feels Like’ rather than just ‘Wind Chill’. Either way, Apple’s Weather app doesn’t have a clue.

As you see above, the temperature when I grabbed this screen was 25F. The next screen shows the wind and the ‘Feels Like’ temperature – and although the wind speed is 9 MPH, the temperature apparently shows no impact.

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Of course, if you know anything about being in a cold wind, you know that 16 MPH winds have a VERY significant impact on how things feel! Here is the calculation used by the National Weather Service, with T as temperature and V as wind velocity:

Wind Chill = 35.74 + 0.6215T – 35.75(V^0.16) + 0.4275T(V^0.16)

Based on that calculation, 25F with a 9 MPH wind feels like 15F. Which is about right, according to the Weather Channel app:

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Here is the full NWS graph:
windchill

It is funny, because I noticed this effect before, and in particular as we had a fire alarm at my work yesterday afternoon – the temperature was 39F and everyone was remarking how warm it was … until we had stood in the parking lot for 20 minutes with 22 MPH winds (Wind Chill 22F, or according to Apple … 39F).

So if you are trying to check for wind chill – don’t trust the Apple Weather app!

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