Originally Posted by Tanic

This weeks sub-tropical jet stream, which coincidentally will be bringing another atmospheric river (I liked Pineapple Express better) to the US West Coast is the culprit. The eastbound flights won't be shortened as much as the westbound flights are lengthened since the airplane spends more time in headwinds than in tailwinds. Thus headwinds have a greater effect. BTW, Bay Area airports are the closest mainland geographically to the islands.