Car seats in winter: puffy coat off, harness snug enough to pass the pinch test, then the coat goes on top

Why a puffy coat is a problem

A harness only works when it’s snug against the child. A puffy coat or snowsuit makes it feel snug when it isn’t: the padding is mostly air. [S1] [S4]

• It flattens in a crash. The force squashes the padding right away, which leaves extra space under the straps. The AAP says a child can then slip through the straps and be thrown from the seat. [S1] [S2]
• It hides slack. Vanderbilt’s program says coats give the false impression that the straps are tight when they’re really several inches too loose. [S6]
• NHTSA agrees. Too much bulk creates extra room in the harness and a loose fit, which puts the child at risk of injury in a crash. [S3]

The coat test: is this one too bulky?

Not sure about a particular coat? CDOT and Vanderbilt describe the same check. It takes a minute in the driveway. [S5] [S6]

1. Coat on. Buckle your child in wearing the coat and tighten the harness until it passes the pinch test. [S5]
2. Unbuckle, don’t loosen. Take your child out without changing the strap length. [S5] [S6]
3. Coat off. Put your child back in without the coat and buckle the harness at the same setting. [S5] [S6]
4. Pinch again. If you can now pinch extra strap at the shoulder, the coat is too bulky to wear under the harness. [S5]

What snug looks like

These checks apply every ride, coat or no coat. [S2] [S4]

• The pinch test. Buckle and tighten, then try to pinch the strap together at your child’s shoulder. If it’s snug, your fingers slide off the webbing. If you can pinch a fold of strap, tighten it. Safe Kids calls a loose harness a common mistake. [S2] [S4]
• Chest clip at armpit level. The AAP says the clip goes at the center of the chest, even with the armpits. [S2] [S6]
• Strap height. Rear-facing, the harness comes from slots at or below the shoulders. Forward-facing, at or just above them. [S2]
• Seat installed tight. If the seat moves more than an inch side to side or front to back at the belt path, it’s not tight enough. [S2]

How to dress them for the car

The idea is to put warmth where it can’t get between your child and the straps. [S1] [S3]

• Thin layers. Start with close-fitting layers like tights, leggings or a long-sleeved bodysuit, then pants and a sweater or thermal shirt. A thin fleece jacket can go on top, and long underwear helps in very cold weather. NHTSA also suggests lightweight fleece over puffy materials. [S1] [S3]
• Coat or blanket over the straps. Buckle up first, then put the coat on backward with the arms through the sleeves, or lay a blanket over the harness. The AAP mentions that some parents like poncho-style coats or jackets that zip down the sides so the back flips forward over the harness. [S1] [S3] [S5]
• Babies get one more layer, on top. The AAP’s rule of thumb is one more layer than an adult wears. Take the coat and blanket off before buckling, then put them back over the straps. [S1]
• Hats, mittens and booties. They add warmth without touching the straps. Keep spare mittens, since wet ones make a child colder. [S1]
• Keep the infant carrier inside. A carrier stored at room temperature pulls less heat from your baby. [S1]
• Watch for overheating. Make the top layer easy to remove once the car warms up. CDOT warns that blankets plus a blasting heater can overheat a baby quickly. [S1] [S5]
• Leave a few extra minutes. Layering and buckling take longer on winter mornings, and so does driving. [S1]

Car seat covers, bunting bags and inserts

This is where shopping can go wrong. The AAP says many retailers sell car seat bundling products that aren’t safe to use in a car seat, and being on a store shelf or sold online doesn’t make one safe. [S1]

• Nothing under the baby. No bunting bag, sleeping bag insert, stroller liner or padding under your child or between your child and the straps. [S1] [S2] [S6]
• If it didn’t come with the seat, it wasn’t crash tested with it. The AAP says to skip extras unless they came with the seat or the seat’s maker approves them for that seat. These add-ons aren’t covered by any federal safety standard. [S1] [S2]
• Covers only over the top. A car seat cover is OK only if it has no layer under the baby. Keep your baby’s face uncovered. CDOT adds: don’t drape a blanket over the entire seat, because it can restrict airflow. [S1] [S5]

Older kids and grown-ups too

The AAP says its winter tips apply to all ages. A puffy coat under a seat belt adds space between the body and the belt, and that’s not a best practice for adults either. For a child in a booster or seat belt, a thinner jacket under the belt and the warm coat on top follows the same idea. [S1]

Every child younger than 13 should ride in the back seat, the AAP says. [S2]

Check the seat itself

Winter is a good time to look the seat over. The AAP says never to use a car seat that is too old for its maker’s limit, has visible cracks, is missing its label or parts, or has been recalled. [S2]

The label shows the date of manufacture and model number. Check recalls with the seat’s maker or NHTSA’s Vehicle Safety Hotline at 888-327-4236, and register the seat so the maker can reach you about a recall. A certified child passenger safety technician can check the fit for you; the National Child Passenger Safety Certification program lists them (877-366-8154). [S2]

And while the car warms up: Vanderbilt’s program says never to run the car in the garage, and never to leave it running with a child inside. Our carbon monoxide alarm guide covers the home side of that risk. [S2] [S6]

What are they wearing?

Pick what your child has on to see what the sources say.

Whatever they’re wearing, finish with the pinch test at the shoulder. [S2] [S4]

Your situation

Pick the one that fits to highlight what the sources say.

Before the first cold morning

Quick answers