Winter Coats and Car Seats: How to Keep Kids Warm and Buckled Safely • Living Life as Moms | Mom Hacks, Toddler Snacks, and Kids Activities

Quick answer: bulky winter coats and snowsuits should not be worn under a car seat harness, because the padding compresses in a crash and leaves slack that can let a child slip out. Dress your child in thin, warm layers such as a fleece top, buckle the harness snugly, then put the coat on backward over the harness or lay a blanket over the child. Check the fit with the pinch test: if you can pinch webbing at the child’s shoulder, tighten the harness. Do not add thick products between the child and the seat unless the car seat manufacturer approves them.

When the temperature drops, getting a toddler into a car seat gets harder. A puffy coat feels like the right way to keep a child warm on the way to the car, and a snug harness over a thick jacket can even look tight. Safety experts warn that this is one of the most common car seat mistakes in cold weather. The good news is that a few simple changes keep kids warm and safe, without extra equipment. This guide is part of our family health and safety guide, and it explains why coats are a problem, how to test the fit and how to keep a child comfortable on winter drives.

Sources: American Academy of Pediatrics (AAP) HealthyChildren.org guidance on car seats and winter clothing; National Highway Traffic Safety Administration (NHTSA) car seat guidance; Children’s Hospital of Philadelphia (CHOP) car seat safety information; Safe Kids Worldwide child passenger safety tips. This article is general information. Always follow your car seat manual and vehicle owner’s manual, and consult a certified child passenger safety technician for help.

Why Puffy Coats Are a Problem

A car seat harness works by holding the child tightly against the seat, so the force of a crash is spread across the strongest parts of the body. It only works if the straps are snug against the child.

A thick coat or snowsuit is filled with air or soft padding. In everyday use, it feels firm. In a crash, the forces compress the padding, and the harness suddenly has extra space. The child can be thrown forward, or even partly out of the harness. Safety experts, including the AAP, therefore recommend that children not wear bulky coats under the harness.

The problem is invisible. A harness that feels tight over a coat may be loose by several inches once the padding flattens. That is why a pinch test, described below, is so useful.

The Pinch Test

Check the harness before every ride in winter, and any time your child wears thick clothing.

Buckle your child in wearing their coat, and tighten the harness until it feels snug.
Unbuckle without loosening the straps, and take the coat off.
Put your child back in the seat and buckle the harness again, with no coat.
Look at the slack. If you can pinch any webbing at the child’s collarbone, the harness is too loose with the coat on. If the strap is flat, with no loose webbing to pinch, the child was safe.
Tighten the harness to the proper snugness, with the chest clip at armpit level and no slack at the shoulders or hips.

The test shows how much the coat compresses. Most puffy coats fail it, while thin fleece jackets usually pass.

Dress in Thin Layers

Layers keep a child warm without adding bulk.

A snug base layer, such as a thermal top or long-sleeve shirt.
A warm middle layer, like a fleece jacket, a sweater or a thin sweatshirt.
Warm pants or leggings and thick socks.
A hat and mittens, which are fine to wear in the seat if they do not interfere with the harness.
Boots or warm shoes.

Take off the heavy outer coat before the child gets into the seat. If you have a short walk to the car, carry the coat and put it on once you arrive. Keep the coat on hand for the walk to the destination.

Ways to Keep Kids Warm Over the Harness

Once the harness is buckled and snug, you can add warmth on top.

Put the coat on backward. Tuck the arms through the sleeves backward, so that the coat covers the chest and arms like a blanket.
Lay a blanket over the harness. Tuck it around the child’s sides and legs. Make sure the blanket does not cover the face.
Use a poncho-style cover that goes over the child and the harness rather than behind or under it.
Pre-warm the car. On cold days, start the engine a few minutes ahead, but never leave a child alone in a running car.
Use the car’s heat. After a few minutes, many kids warm up and may not need extra layers.

Add-Ons and Covers: What to Know

Many products claim to keep kids warm in a car seat. The rule from child passenger safety experts is simple: nothing should go between the child and the seat, or under the harness, unless the car seat manufacturer made or approved it.

Thick liners, inserts and bunting bags that go behind or under the child can change how the harness fits and can interfere with safety. Products sold separately are not crash-tested with your seat unless the manufacturer says so.
Shower-cap-style covers that fit over the top of an infant carrier, with no layer behind the baby, are generally considered safe, as long as the baby’s face is clear and the cover does not trap heat. Check with the manufacturer.
Fleece or knit covers that fit over the harness are generally considered safe when they do not add padding between the child and the seat.

Read the car seat manual for what is allowed. If you are not sure whether a product is safe, call the manufacturer or visit a child passenger safety technician.

Infants and Winter Rides

Babies need extra attention in cold weather.

A thin layer plus a hat is often enough, since the car heats up quickly.
Do not leave a baby in a coat in the carrier, because overheating can also be a danger.
Keep the harness at or below the shoulders for rear-facing infants, snug, with the chest clip at armpit level.
Avoid blankets near the face. Safe sleep guidelines apply in the car, and the baby’s face should always be uncovered. See our guide to safe sleep for babies for the basics.
Check on the baby often, and never leave a sleeping baby alone in a car seat outside the car or in a parked car.

Remember that infant car seats are for travel. A baby who falls asleep in the car seat should be moved to a flat, firm sleep surface when you arrive.

Older Kids and Boosters

Kids in booster seats use the vehicle seat belt, and bulky coats cause the same problem. The belt should lie flat across the chest and low on the hips. A thick coat adds space between the body and the belt. Have your child take off a puffy coat before buckling up, then lay the coat across their lap if they are cold. Check that the lap belt stays across the upper thighs, not the stomach.

Teens often resist taking coats off. Explain that the coat is still within reach and that the belt does its job only when it fits close to the body. Our guide to car seat stages by age and size shows when kids move from harness to booster to seat belt.

Common Winter Car Seat Mistakes

Buckling the harness over a puffy coat or snowsuit.
Using a thick liner or sleeping bag under the child.
Leaving the chest clip too low. It should sit at armpit level.
Letting hats, scarves or hoods get in the way of the harness or the child’s breathing.
Skipping the pinch test.
Warming up the car with a child inside and leaving the car.
Forgetting to clean off snow and ice from shoes and seats, which can make the straps slip or cause a child to slip out of the seat.

Keeping Kids Warm Without the Car Seat Stress

Cold-weather driving works best with a routine.

Dress for the car, with thin layers and a hat.
Carry the coat to the car, and keep it in the front seat or on your lap.
Buckle, test and tighten the harness.
Add the blanket or backward coat.
Start the car heat early, and check your child often.
Keep spare mittens and a blanket in the car in case of a breakdown.

Making the Routine Work at Drop-Off

Busy mornings are when shortcuts creep in. A few small habits make the routine automatic, even when you are late for school or child care.

Keep a coat hook or bag by the door for each child, so the heavy jacket travels with you instead of on the child.
Leave a spare pair of mittens and a hat in the car, so no one has to dress up again for a short walk.
Tell other caregivers. Grandparents, babysitters and carpool parents may not know about the coat rule. A short note taped inside the car seat, or a quick talk, helps everyone follow it.
Practice once on a calm weekend, so that children get used to the backward coat or the blanket and treat it as a game.
Give older kids a role. A child who helps check the harness or hold the coat is less likely to complain.

Child care centers sometimes ask parents to bring a coat for outdoor play. Pack it in the child’s bag, and put it on when you arrive.

Cold Weather Care for Little Hands and Feet

Kids lose heat quickly through uncovered skin. Mittens often work better than gloves for small children, since fingers stay warmer together. Waterproof boots with a warm sock layer keep feet dry. Look for signs of cold injury when you arrive anywhere after time outdoors: skin that looks pale, waxy or very red, numbness or stinging, or a child who stops complaining because their fingers no longer feel anything. Move the child inside, remove wet clothing, warm the area gradually with lukewarm water, not hot, and call a doctor if skin stays numb or changes color. For more on cold-weather play, see our guide to sledding and winter outdoor safety.

Checking the Seat After Snow and Ice

Snow brought in on boots can melt into the seat and make straps damp and slippery. Brush snow and slush off shoes before climbing in, and wipe down buckles and straps if they get wet. Ice can freeze buckles shut, so thaw them gently with the car’s heat instead of forcing them. Never use hot water or a hair dryer on a car seat. Check the manual for cleaning instructions, because soap and some products can weaken the straps.

Emergency Supplies for Winter Trips

On long winter drives, pack an emergency kit with a few extra blankets, warm hats and gloves, snacks, water, a flashlight, a phone charger and a first aid kit. If your car breaks down, call for help, keep the heat on if safe and run the engine only if the exhaust pipe is clear of snow, since blocked tailpipes can cause carbon monoxide to enter the car. Our family first aid kit checklist lists supplies worth having on hand.

When a Child Complains of the Cold

Some children say they are cold the moment they sit down. Reassure them that the car will warm up soon, offer a blanket and keep the fan on low. For a child who truly cannot get warm, check the harness for fit, and consider warmer base layers rather than a coat. If a child is shivering, pale or has cold, stiff hands and feet after being outdoors, move them to a warm place and contact a doctor if they do not improve.

Frequently Asked Questions

Can my child wear a winter coat in the car seat?

A thin, close-fitting jacket may pass the pinch test, but bulky coats and snowsuits should not be worn under the harness. Use the pinch test to check.

What is the pinch test for a car seat?

After tightening the harness, if you can pinch any webbing at the child’s shoulder, the harness is too loose and needs tightening.

How do I keep my baby warm in a car seat?

Dress your baby in thin layers and a hat, buckle the harness snugly and lay a blanket over the harness, keeping the face clear.

Are car seat covers and bunting bags safe?

Products that go between the child and the seat or under the harness are not recommended unless the manufacturer approved them. Covers that fit over the top without a layer behind the baby are generally considered safe.