Sorry Apple Weather, That Is NOT How You Calculate Wind Chill

Weather Apps and Stations Science Offbeat iPhone Apps iPad Apps

Wind Chill Factor

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 30F. The next screen shows the wind and the ‘Feels Like’ temperature – and although the wind speed is 16 MPH, the temperature apparently shows no impact.

Weather Apps and Stations Science Offbeat iPhone Apps iPad Apps   Weather Apps and Stations Science Offbeat iPhone Apps iPad Apps

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, 30F with a 16 MPH wind feels like 19F. Which is about right. Here is the full NWS graph:

Weather Apps and Stations Science Offbeat iPhone Apps iPad Apps   Weather Apps and Stations Science Offbeat iPhone Apps iPad Apps   Weather Apps and Stations Science Offbeat iPhone Apps iPad Apps

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).

But seeing the post from Carly brought it back to my mind, and as I stopped by the market earlier I was blasted by the wind and decided to check … and this is what I found.

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

About the Author

Michael Anderson
I have loved technology for as long as I can remember - and have been a computer gamer since the PDP-10! Mobile Technology has played a major role in my life - I have used an electronic companion since the HP95LX more than 20 years ago, and have been a 'Laptop First' person since my Compaq LTE Lite 3/20 and Powerbook 170 back in 1991! As an avid gamer and gadget-junkie I was constantly asked for my opinions on new technology, which led to writing small blurbs ... and eventually becoming a reviewer many years ago. My family is my biggest priority in life, and they alternate between loving and tolerating my gaming and gadget hobbies ... but ultimately benefits from the addition of technology to our lives!

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