How to Keep Baby Warm in Car Seat: 12 Tips Parents Need

The last thing parents want is their baby to be uncomfortable, and when winter arrives, you need to know how to keep your baby warm in car seat.

One thing that seems to send all parents into a frenzy is car seat safety, but it’s a vital topic nonetheless. A few years ago, the topic of winter coats and car seats come to the forefront, and many parents, myself included, realized that we were doing things wrong.

No one ever told us that winter coats and car seats were a big no-no!

When you’re facing low temperatures, sometimes single digits, you start to wonder how it’s possible to keep your baby warm in a car seat, especially if you don’t have a garage.

Here are some tips that work and you need to try.

This post may contain affiliate links which I would receive a small commission should you make a purchase.

Can Babies Wear Coats in a Car Seat?

No, babies cannot wear thick coats in a car seat. A general rule for parents to remember is that bulky clothing, including winter coats and snowsuits, should never be worn underneath the harness of a car seat.

When I first learned about this, I was confused. Wouldn’t my baby be cold? My parents were SURE that I would freeze my child if I didn’t let him wear a winter coat in the car.

Science tells us why winter coats in a car seat are a bad idea.

During a car crash, the fluffy padding flattens out from the force, so there is extra space under the harness. Any extra space under the harness is a serious danger because your child can slip through the straps, ejecting from the seat.

It’s believed that puffy winter coats and snowsuits leave an average of two to four inches of slack in the straps.

Can Babies Wear a Snowsuit in a Car Seat?

Like winter coats, snowsuits aren’t safe to use in a car seat. They’re air-filled suits, and no matter how hard you tighten the straps, it’s impossible to remove all the air.

However, during car crashes, the air is pushed out of the snowsuit, leaving slack in the straps.

How to Test to See if Your Baby’s Coat is Safe in a Car Seat

Not all coats are the same thickness, so you might wonder if your baby’s coat is safe in a car seat.

Here’s a simple way to check.

  • Put your baby’s coat on and place them into the car seat, fastening the harness. Tighten the harness until there is no more pinch in the webbing between your thumb and forefinger.
  • Remove your child out of the car seat, take off their coat, and place your child back into the car seat. Make sure to fasten and buckle the harness.
  • If the webbing can be pinched between your thumb and forefinger, the coat is too bulky.

12 Tips to Keep Baby Warm in Car Seat

Once parents learn that their babies cannot wear coats in the car, they often wonder how they can keep their baby warm in the car seat.

Here are a few tips to help you make sure your baby is snug and cozy without a big winter coat.

1. Bring the Car Seat Carrier Inside

Little babies often use infant bucket car seats, so in the middle of the winter, bring the carrier portion of the infant seat when not in use.

That helps to keep the seat at room temperature and lets you get your baby ready in the seat without them being cold.

2. Warm the Car First

This option always exists in the winter – try warming up your car ahead of time. Make sure the temperature is comfortable for everyone, and get the car warm before putting your baby inside.

3. Dress in Thin Layers

Thin layers is the best way to keep your baby warm instead of using a thick winter coat.

Start with a snug-fitting layer on the bottom; leggings or long-sleeved bodysuits are perfect. Then, add pants and a thicker top, like a sweater.

After that, it’s safe for your baby to wear a thin fleece jacket. If you live somewhere with super cold temperatures, long underwear is also another safe option.

The general rule is that infants need to wear one more layer than adults. So, if you’re comfortable with a sweater, your baby needs a sweater and a thin bodysuit underneath. If a coat keeps you wear, then your baby also needs a blanket on top.

Dressing your baby in two to four thin, tight layers is as effective at keeping your baby warm as wearing a winter coat full of air.

4. Wear Hoodies

I love baby hoodies; they’re the cutest thing. My babies always pulled off hats, but hoodies are harder for them to remove.

Wearing thin, adorable hoodies is a great way to keep your baby warmer and make sure they keep a hat over their ears. At the same time, hoodies won’t add bulk that would negatively impact the car seat safety.

5. Bring Hats, Mittens, Socks and Booties

Wearing hats, mittens, socks, or booties are other ways that your baby can stay warm in the car seat without bothering their car seat straps.

My babies hands get cold so easily, so little sets of mittens make sense!

Humans lose body eat through our ears, so make sure you put hats on your baby as well.

6. Sweaters and Light Jackets are OK!

Sweater and thin, fleece jackets are perfect for the car seat. We love fleece and sweaters because they don’t have padding – so you don’t need to worry about too much space with the straps – and they still work at keeping your child warm.

7. Put Your Child’s Coat on Backwards

Another trick that parents love is putting the child’s coat on backward! Put your baby into their car seat the proper way, and put their arms through the coat with the back side on their stomach.

It’s simple and effective. Plus, if your car gets too hot, it’s easy to remove without taking your baby out of the car seat.

8. Keep Car Blankets in Your Vehicle

We keep car blankets in our vehicle at all times; I’ll forget them in the house otherwise. Place a blanket over the top of the harness straps after you buckle your baby up.

I use a small cubed container and keep it in the middle of my car. The folded blankets stay in there, so we can use them as needed.

9. Use a Car Seat Poncho

Instead of blankets, use car seat ponchos over top your baby to keep them warm.

Kids love ponchos, and most of them have cool hoodies and fabrics. This goes over your child’s head, but you can flip the back behind your baby so nothing comes between your child and the car seat.

10. Use Products That Go Over the Car Seat

Some products, like car seat covers, are safe to use with a car seat, so long as no layers go underneath the baby. Nothing belongs underneath your baby because it might cause you to loosen the straps, even slightly, and that’s not safe.

Your baby’s face should never be covered; suffocation is a real hazard.

Also, understand that just because it’s sold in stores doesn’t mean it’s safe to use. We see baby gear products recalled all the time due to safety concerns.

11. Don’t Overheat Your Baby!

All this talk about multiple layers means that your baby has an increased risk of overheating. We spend all this time worrying that your baby will be too cold, forgetting that the opposite can happen.

Watch for any signs that your baby might be too hot and be ready to take off layers as needed to keep your baby comfortable in the car.

12. Keep an Emergency Bag in Your Car

Always keep an emergency bag in your car with supplies you might need, such as:

  • Blankets
  • Change of Clothing
  • Hats and Gloves
  • Water
  • Non-Perishable Snacks

Recommended Winter Gear to Wear in a Car Seat

Some products ARE safe for car seat use, so here are some safe options that will keep your baby cozy without any concerns.

1. 7 AM Enfant Baby Car Seat Baby Wrap

The Nido is a baby wrap that adapts to car seats and strollers; it’s a safe alternative to winter coats and multiple layers.

The reason that the Nido is so highly recommended is the oval hole in the back that lets you put this on after your baby is buckled up snuggly. It’ll keep your baby super warm, and it works for infant and convertible seats.

2. 7 AM Enfant Cocoon Baby Cover

If you live somewhere considerably cold, one of the warmest options for an infant car seat is this Cocoon Baby Cover. It has a temperature rating of -4 degrees F.

The Cocoon is a “shower cap” style that fits over the infant car seat, and it’s totally safe since nothing goes under your baby.

This is a great choice if you need to keep the wind and snow off your baby.

3. Columbia Fleece Jackets

One of the our family’s favorite things to wear in the winter are our Columbia fleeces. They’re affordable and use a thick fleece that is warm without fit snuggly to your child’s body.

Columbia sells jackets for all sizes, including adults!

4. Columbia Snowtop Bunting

So long as you use the right size, the Snowtop Bunting is another safe option for car seat use. It keeps your baby warm but not too warm. I wouldn’t use this for super cold days, but it is the right thickness for chilly days.


Once winter arrives, you’ll want to try all these tricks to keep baby warm in a car seat. The most important ones to remember are to warm up the car seat ahead of time and wearing several thin, warm layers instead of a bulky coat.

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