What’s the Deal with Winter Coats in Car Seats?

winter jackets and car seats

Winter coats in car seats: updated September 2023

Winter coats in car seats has become a hot topic in the parenting corner of social media.

I still remember my feeling of complete and utter confusion when I first learned that children should not be strapped into their car seats in their winter jackets, snowsuits or thick bunting bags. I had so many questions.

This was long before becoming a car seat tech and long before discovering that I was doing a lot more things wrong with my car seat than just cramming my son into it with his Michelin-man-style snowsuit.

So if you’re like me circa 2013, and you have questions, you have doubts, you feel like you’ve fallen into the Upside Down where the strangest thing you’ve ever heard is that car seats and winter coats are enemies … this post is for you.

Who says winter coats in car seats can be dangerous?

The car seat manufacturer says, that’s who.

winter jackets and car seats

And why should we care what the car seat manufacturer says about how their safety device should be used? Well, because a car seat isn’t just some baby fashion accessory—it’s a safety device. It is designed and tested in very specific circumstances to protect our children from injury and yes, even from death.

And if we don’t use the car seat as prescribed by the manufacturer, then we do not know how it will perform, and we are taking an unnecessary risk with our child’s safety. (I’ve said it once, I’ll say it again: motor vehicle collisions are a leading cause of accidental death and injury for young children, not a once-in-a-blue-moon kind of event.)

Car seats and booster seats are not tested on child dummies wearing snowsuits. They are tested on child dummies wearing normal, close-fitting clothing that allows for the harness or seatbelt to sit as close to the child’s body as possible.

And yes, the same is true for adults. As in no, we should not be wearing an enormous winter parka while driving or riding in a car.

winter jackets and car seats

But why is it dangerous to use winter coats in car seats?

Think about yourself in an especially thick winter jacket. To work properly, the seat belt is supposed to be tightly fitted against the bony parts of your body. Your thick jacket creates a gap between you and the belt, meaning in a collision the forward movement of your body will be increased.

You’ll notice that when you strap your child into their seat wearing a big snowsuit, you have to loosen the harness. And sure, you tighten it up again, but it’s not as tight as when they’re riding in just a sweatshirt and pants. In my experience, it is awkward as heck to cram a snowsuit-clad child into their car seat and appropriately adjust their harness.

In the event of a collision, we want our child’s body to be held in place by their harness:

  • We want to minimize the forward movement of a forward-facing or boostered child as much as possible to avoid injury to the neck and spine.
  • We want the upward movement of a rear-facing child to be minimal to avoid head excursion (their head hitting the seatback behind them).
  • We want the harness to keep the child in the seat—an improperly tightened harness can put the child at risk of ejection.

A snowsuit can cause the harness to be improperly tightened. The force of a collision will quickly squish out all the air inside the winter jacket and create a gap between the child and the harness (or seat belt), which means their bodies may move more than necessary and that their seat will not perform as it is designed to.

So what you’re saying is our kids should be naked in their seats?

Nope, I am absolutely not saying that. I am about to embark on my seventh winter with children in car seats, and I promise that none of them are naked. And yes, I live where it is cold AF.

Use layers!

What we want to do is dress our children so they’re car-seat ready. LAYERS, folks. LAYERS.

In the winter, start the day by dressing your kids in close-fitting layers and thermal fabrics. Honestly, whether you’re going out in the car or just the stroller, having a warm base layer just makes getting out of the house easier.

No winter jacket in the car seat doesn’t mean no jacket at all in the car seat. There are a wide variety of jackets that are perfectly fine to use in a car seat.

Put warm layers on TOP of the child once they are buckled: this could be their winter jacket on backwards, blankets or their car seat poncho.

How do I get all my semi-naked children out to the car when it’s cold out?

Let me state again for the record: no naked or semi-naked children are being carted out to their car seats in the winter. However, I do not recommend bringing kids out to the car in their full snow-ready apparel because they will have to shed some of it before they get strapped in.

Start the day car-seat ready

winter jackets and car seats

If you need to leave the house in the car during the day (which for me is every day), make your life easier by dressing the kids appropriately as soon as they get up. Personally, I just keep each kid’s entire wardrobe car-seat friendly which, conveniently, also makes it perfect for babywearing and as a base-layer if we need to throw on snowsuits.

I avoid thick, lined sweaters and sweatshirts with giant hoods. For one thing, they’re usually way too warm for indoors, and for another, they’re a nightmare to squish into the car seat, and they’re too thick and warm to go under a snowsuit if we’re playing outside anyway. (Not too mention too warm for babywearing and awkward to fit under a sleeved bib at mealtime.)

Last year the twins’ winter uniform was a onesie (short or long sleeve) under a fleece footed sleeper, or a onesie under a close-fitting sweater or sweatshirt with fleece pants and knee socks.

For the toddler to school-age group, fleece-lined leggings or sweatpants are the best!! I usually put knee socks under these, although long underwear or tights work too. Then I do a T-shirt with a sweater on top, or a short-sleeve tee overtop of a long-sleeve tee. Fleece is the most affordable warm but thin fabric, but you can also look for merino wool pieces for your base layers if you want to get fancy!

How I get my kids out to the car and keep them warm on the road depends on their age and car seat stage

Remember that while it may be colder than Winterfell outside, it doesn’t take long for the inside of the vehicle to warm up. If you’re uncomfortably hot in your parka behind the wheel, your kids are going to be even hotter squished into their seats in their full-on winter gear. Harnessed kids cannot remove layers to prevent overheating unless those layers are placed on top of them.

For all ages and stages, appropriate winter accessories that don’t interfere with the car seat and are also easily removed as the vehicle heats up will make a huge difference in keeping the child warm on the way to and once inside the car. A hat, neck-warmer, mittens and warm boots are a must for all stages.

1.     Infants in bucket seats

These are the easiest babies to keep warm in cars in the winter. You can buckle baby in wearing just their warm base layers. I tend to favour a long-sleeve onesie under a polar fleece footed sleeper, a neck warmer, a hat and slippers. Once you’ve buckled baby in, apply warm layers as required.

Honestly, a thick blanket swaddled around baby is often PLENTY if you’re just going from house to vehicle, vehicle to indoor destination. Remember that once you get driving, the vehicle will warm up and you do not want to overheat baby!

Shower-cap-style covers provide warmth and shelter from the elements. These covers go over top of the car seat but do not interfere with the harness. Remove or fully open this type of cover once in the vehicle to avoid suffocation and overheating. Remember that to a car seat manufacturer, even a shower-cap-style cover is considered an untested third-party product, and the recommendation is to remove it completely in the vehicle.

The best, thin-but-warm jacket and pants option I’ve found for smaller babies is the MEC Bundle Up jacket and matching pants (formerly called “Cocoon”). The smallest size is 6 months, and my twins fit them starting at about 9 months. My daughter wore the 18 m size when she was 2.

2.     Non-walking (or not awesome at walking) toddlers in convertible car seats

Once baby is out of the bucket seat, you have a bit more work to do, but I assure you it is doable. I’m doing it with twin toddlers and two older kids!

Children not yet walking or whom you do not want walking out to the car can be dressed in their warm layers with a single-layer polar fleece jacket or compressible down-style jacket on, and then carried out to the car with a blanket on top or in a car seat poncho.

There are some one-piece polar fleece or compressible suits that are theoretically thin enough for car seat use. The problem with choosing a one-piece option is that unless it fits baby perfectly, you tend to wind up with a lot of excess fabric around the middle that just bunches up when baby is seated and makes it harder to adjust the harness.

Many crafters make some absolutely adorable car seat ponchos that will last multiple seasons; however, you can also make your own car seat poncho using a fleece blanket from the dollar store or IKEA and a pair of scissors.

Other options include “Snuggie” style wearable blankets. I’ve seen these sleeved blankets with kids’ favourite characters on them at Shoppers Drug Mart. Once seated and buckled, the child can put their arms through and be nice and cozy. They can also wear it as you carry them out to the vehicle. Another very simple option is having the child wear their winter coat backwards on top of them for the ride.

A blanket with sleeves isn’t just for chillin’ on the sofa … could be ideal in the car!

Snow pants or snowsuits should be put on upon arrival at your destination. If the child wears their snowpants or suit out to the car, you can even pull the pants down to their ankles while they’re in their car seat, then pull them up upon arrival. Personally, I choose a car-seat jacket that fits under my kid’s winter jacket or snowsuit, which I put on them while they stand up in the trunk or inside the van.

3.     Walking children in rear or forward-facing harnessed seats

My daughter is wearing her MEC Cocoon (now called Bundle Up) jacket and my son is wearing the inner portion of his Columbia Whirlibird.

While a babe in arms can easily be covered with a blanket on the way to the car, it’s a bit of a sport to try and get a toddler or even preschooler to keep themselves appropriately blanketed as they trudge out to the vehicle. This is why I particularly like car seat ponchos for this stage since they can be worn out to the car.

Moues&Hatter Car Seat Poncho

If you have a remote car starter, heated garage or simply start the car up a few minutes before it’s loading time (sorry global warming), your child may be perfectly fine heading out to the vehicle in their compressible down jacket and appropriate winter accessories. Throw a blanket on once they’re seated and you’re ready to roll. My older kids head out to the car even in the coldest of winter temperatures with their winter accessories and their car-seat-safe coat because it’s a very short walk.

L to R: MEC Bundle Up; George (Walmart) Puffer; Patagonia Down Sweater; Columbia single-layer fleece

For snow pants and snowsuits, I do the same as with kids in stage 2.

4.     Booster riders

Our most autonomous passengers are pretty easy to handle when it comes to winter apparel. And YES, even booster riders need to avoid full-on snowsuits in the car. (And full-on hockey gear for that matter.)

The easiest workaround is to simply unzip the child’s coat before buckling so that the shoulder and lap belts pass close to their body over their regular clothes.

In terms of snow pants, I don’t have a hard and fast rule, but if they’re especially thick and prevent the lap belt from being snug against the tops of the thighs, the easiest thing to do is either put snow pants on at your destination or just slide them down around the knees for the ride. Bigger kids may even find it hard to fit their bums into their booster seats with their snow pants on, so they’ll be much more comfortable without them.

I love dual-layer coat systems, which have a compressible down jacket that fits under the waterproof shell portion to create a full winter jacket. My son will head out to the vehicle with just the inner layer on, then put the top layer on once he gets to the destination. The one we love is the Columbia Whirlbird II Interchange Jacket.

What about car-seat-safe coats?

Tempo Outerwear

We are very excited to be testing out the Tempo Outerwear Duo coat this winter (2023-24!). We have ben using the inner layer on colder mornings and have tested out the design in a car seat, as you can check out in the video below.

This jacket is designed by a Canadian mom and is meant to be used year-round since it can be worn all together, or the top or bottom layer can be worn alone. The long, foldable cuffs mean my larger twin (age 5) and my daughter (age 8) both fit the 5T size. You can use coupon code CARSEATCUBS to receive a free neckwarmer with purchase.

View this post on Instagram

A post shared by Calgary Car Seat Cubs (@carseatcubs)

Road Coat

The Road Coat is designed to unzip to expose a thinner layer of coat exactly where the car seat straps lay on the child’s body. It’s a super smart design and the coat itself is warm enough for winter use outdoors. The price tag is not within reach of all families, but the techs I know who’ve used it are definitely big fans.Read The Monarch Mommy’s review of the Road Coat.

How do I know if I’ve chosen a coat that’s car seat safe?

There is no single jacket on the market that is going to be a universally perfect option for the car seat. Remember that it’s important for the jacket to fit the child well. If it’s too big for them, then there will be extra fabric bunching up and creating space between them and their harness. Look for coats that are marketed as “compressible” or “packable.” Down-filled ones are great, but they can be pricier. There are plenty of poly-filled options out there, including one I see every year at Walmart that’s around $15.

Your child’s car seat coat isn’t going to be their winter coat also, unless it’s specifically designed as such (like the Road Coat) or you live somewhere with mild winters. Think of it as a base layer that their official outdoor-winter-play coat can go on top of. Consider 2-in-1 style winter jackets that come with the waterproof outer shell and the down-filled inner layer if you only want to buy one coat. (We love the Columbia Whirlbird II Interchange for this!)

To make sure your child’s coat doesn’t interfere with their car seat harness, first buckle them into their seat wearing their normal clothes, and make sure the harness passes the pinch test. Then, unbuckle them without loosening the harness. Put them into their new coat. Put them back in their seat. Do you have to loosen the harness significantly for them to fit in with the new coat? It’s probably too bulky. (You can see a demo of this technique in the Tempo Outerwear video above.)

My oldest is wearing the inner layer of his Columbia Whirlbird, Cub Twin B (who I am now realizing DOES look like his older brother) is in a Gap Cold Control Puffer.

Overall, use your best judgment. You likely have an idea of how much you loosen and tighten your child’s harness when they’re in their normal clothes or a light jacket. The majority of true winter jackets, since they are multi-layered and thick to keep us warm—and since many of us penny-pinching parents buy a size slightly too big to maximize wearing longevity—are far too thick to ensure proper harness adjustment (as well as too warm for poor kiddos in a heated vehicle).

Jackets I recommend:

Remember that the jacket must fit the child snugly: excess bulk from an oversized coat is going to interfere with proper harness tightening. When I explain how to choose a jacket to my clients, I emphasize how a “packable” insulated jacket can be rolled up into a tiny ball; often they even come with a little sac to pack them into. A traditional winter coat with, say, a thick fleece or sherpa lining, cannot do this and is too thick.

Packable jacket on Amazon

What are your favourite strategies for keeping kids safe and warm on the road in winter?

If you’re looking for a Child Passenger Safety Technician, you can find me over at Car Seat Cubs! I can meet you online (Canada-wide) or in person in Calgary!

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Welcome to my Wolf Pack!

My name is Lindsay and I am a 40-year-old mama of four trying to live an eco-friendly, budget-friendly life! I am a substitute teacher and Child Passenger Safety technician in Calgary, Alberta. Join me on my adventures!

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