Winter tire pressure

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'16 CX-9, '19 GTI
My owner's manual says that "snow tires" should be inflated 4.3 psi higher than what's stated on the tire pressure label. Why would that be? As I understand it, when the air temp decreases 10 degrees, the tire pressure decreases about 1 psi. So does the manual assume that we'll be measuring the tire pressure in a garage that's 40 degrees warmer than the outside temp? That seems pretty extreme.

Anybody have another explanation?

Patrick.
 
Winter tires are made of a much softer rubber compound and as a result, they do not hold their shape as well. Extra inflation pressure helps the car to maintain a moderately stock driveability "feel"
 
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