Question 1

Does wind chill affect a car or a pipe?

Accepted Answer

No. Wind makes objects cool faster to the air temperature, but it cannot take them below it. Only something generating its own heat — a body — feels a wind chill.

Question 2

When does frostbite become a real risk?

Accepted Answer

Around −28 °C of wind chill it takes about half an hour of exposure, at −38 about ten minutes, and below −48 a few minutes are enough.

Question 3

Why does the formula stop at 10 °C?

Accepted Answer

That is the range the formula was set up for, not a temperature at which the body switches how it loses heat. Above it the formula is not used; in the heat, the heat index is the relevant figure.

Question 4

Does it work at very high wind speeds?

Accepted Answer

It flattens out. Past about fifteen metres a second the boundary layer is already gone, so more wind takes little further off the effective temperature.

Question 5

Why does doubling the wind not double the chill?

Accepted Answer

Because the wind enters the formula raised to the power 0.16, not to the power one. Going from 5 to 10 m/s at −10 °C takes the felt temperature from −17.4 to −20.3, not to −25. Most of the effect is spent in the first few metres per second, when the still layer of warm air against the skin is stripped away.

Question 6

Should I dress for the air temperature or for the felt one?

Accepted Answer

For the felt one where skin is exposed — face, ears, fingers — because that is exactly what the index describes. For everything under a jacket, the air temperature is the honest figure: the wind cools a covered body only as fast as it gets through the layers, which is what windproof fabric is for.

Wind speed	In km/h	Feels like	Colder by
0.5 m/s	1.8	outside the formula's range	—
5 m/s	18	−17.4 °C	7.4
10 m/s	36	−20.3 °C	10.3
15 m/s	54	−22.1 °C	12.1

Wind Chill Calculator

Result

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