For those worried about the wind gusts and such, most rides at Kings Dominion don't usually close until wind gusts reach the 30s. The taller rides in the park (Drop Tower, Windseeker) keep track of the wind speed and make the call to temporarily delay operation if need be. Tallest rides usually close first in a case like this (aforementioned rides, i305, etc.). I cannot speak for how wind affects the speed of a coaster, but I assume it wouldn't affect it too much unless the wind reaches 30mph or above. So with that being said, I wouldn't worry at all about 15-20mph.
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