I go by the rule of one extra layer than you would wear. Plus a hat on his head and a blanket over him.
@Gabrielle yeah sorry this was just for out and about, not in a car seat, completely aware of not being layered up in a car seat was more for walking about outdoors, should have specified apologies
They definitely should not be dressed in that much in a car seat. If you’re walking around in a stroller outside then sure but their layers need to come off in their seats. For us we just have a nice cozy blanket and we will do a long sleeve onesie and pants. With maybe a cardigan or something. As it gets colder and if we actually go outside for a long time during the holidays then we will bundle up a bit more. But not just to go from car to house or store. Only if we are out for a long time outside