This is why you should wear several layers of clothing rather than one heavy garment. If there is a wind a top layer of tightly woven, snugly fitting, windproof clothing will help keep you warm. Get used to removing or adjusting clothing to keep you comfortable and to provide ventilation so water vapor from sweat can escape. Check every ten minutes or so to be sure there is no loss of feeling in toes, feet, fingers, hands, ears or nose, especially if you have been sitting or resting. Frequently check children, the elderly the infirm or incapacitated to be sure they are alert.
Grogginess can be a sign of hypothermia.
Check to see that their extremities are warm. Cold or stiff fingers and toes may be showing early signs of cold injury or frostbite. Even if you don't think it's a particularly cold day, believe anyone who tells you they feel sleepy or chilled. Take immediate action to get them to a warm shelter. Hypothermia can occur even when the air temperature is 65F, especially if clothing is damp and there's a wind.