How to tell your girlfriend that it's cold and pay more attention to keep warm? That's more considerate,

Girls are emotional animals, and most of them prefer action. You might as well buy her gloves and hats (be sure to follow her aesthetic point of view). When you meet outside, put the scarf around the girl gently and put your hand in your sleeve when you walk. Check the weather forecast at night, send it to her or call her gently. Your concern is her warmth in winter.