Wind, as like as all wx, to be considered from 1 hr before earliest ETA to 1 ur after latest ETA. Do not know the reported GS rule of thumb.
If wx do not allow to consider suitable an adequate airport you have to find another way to reach destn.
From Europe to Americas you can consider nothern routing via Iceland taking into account Greenland apt or the Blue Spruce routes. With refuelling stop in Canada Newfounland.