How do you keep a child warm and safe in their car seat during the winter months? Bulky clothing, including winter coats and snowsuits, should not be worn underneath the harness of Baby it's cold outside: Coats and Car Seats IWK Child Safety Link Keep your children snug and secure in colder weather. Parents and caregivers typically dress their children in winter coats. But it's important to know that heavy coats can interfere with the proper Baby Winter Clothes Essential Checklist Deux par deux Deux par Deux Baby Winter Clothes Essential Checklist Deux par deux Deux par Deux Winter Car Seat Safety