Too Hot or Too Cold? Exactly How To Dress Baby For Sleep In Every Season

Before we jump into clothing choices, let’s quickly cover the ‘why’. Unlike us, newborns and young infants aren’t very good at regulating their own body temperature. They can lose heat rapidly, but more importantly for sleep safety, they can overheat easily and can’t just kick off the covers like we can. This is a crucial piece of the safe sleep puzzle.

The American Academy of Pediatrics (AAP) warns that overheating can increase the risk of Sudden Infant Death Syndrome (SIDS). This isn’t meant to scare you, but to empower you with knowledge. By keeping your baby at a comfortable temperature, you are actively creating a safer sleep environment.

The Ideal Sleep Environment

So, what’s the ‘just right’ temperature? Most experts agree that a room temperature between 68°F and 72°F (20°C to 22°C) is ideal for a sleeping baby. This might feel a little cool to you, but it’s perfect for a baby who is dressed in appropriate sleepwear.

The Ultimate Temperature Check

Forget feeling their tiny hands or feet! It’s normal for a baby’s extremities to feel cool to the touch because their circulatory system is still developing. The most reliable way to gauge their core temperature is to place two fingers on the back of their neck or on their chest. If it feels warm and dry, they’re comfortable. If it’s sweaty or hot, they’re likely too warm. If it feels cool, you might consider adding a layer.

Safety First: Remember the ABCs of safe sleep: Alone on their Back in a Crib (or bassinet/pack-and-play). This means no loose blankets, pillows, bumpers, or stuffed animals in the sleep space.

If you’ve shopped for a sleep sack or swaddle, you’ve probably seen the term ‘TOG’ followed by a number. It sounds technical, but it’s actually your best friend in this process! TOG stands for Thermal Overall Grade, and it’s simply a standard measurement of how much heat a garment retains. The higher the TOG rating, the warmer the product.

Think of it like the tog rating on your own duvet. You wouldn’t use a thick winter comforter in the middle of July, right? It’s the same principle for your baby. Using TOG ratings takes the guesswork out of layering. Instead of piling on blankets (which are unsafe for babies under one), you can choose a single, wearable blanket with the perfect TOG for your nursery’s temperature.

Here’s a simple breakdown of what those numbers generally mean:

Now let’s put it all together! Here is a detailed, season-by-season guide. The key is to check your thermostat or a room thermometer to know the actual temperature in the baby’s room, as outdoor weather doesn’t always reflect the indoor climate. The recommendations below assume you are not using any loose blankets.

Summer Nights (Room Temp: 75°F / 24°C and above)

During hot summer months, less is more. The goal is to keep your baby cool and prevent overheating. A fan can help circulate air, but make sure it’s not blowing directly on the baby.

• What to wear: A short-sleeve onesie or even just a diaper.
• Sleepwear: A lightweight swaddle or sleep sack with a 0.5 TOG rating.

Spring & Fall (Room Temp: 69-74°F / 21-23°C)

These transitional seasons can be tricky, with temperatures fluctuating. This is where the standard 1.0 TOG sleep sack becomes a nursery staple.

• What to wear: A long-sleeve cotton onesie or footed pajamas.
• Sleepwear: A 1.0 TOG swaddle or sleep sack.

Winter Chill (Room Temp: 61-68°F / 16-20°C)

When it’s cold outside, we’re tempted to bundle our babies up like little marshmallows. Resist the urge! A cozy sleep sack over a single layer of pajamas is often plenty.

• What to wear: Cotton or fleece long-sleeve footed pajamas.
• Sleepwear: A warmer, quilted sleep sack with a 2.5 TOG rating.

A Note on Hats: Never put a hat on your baby for sleep indoors. Babies regulate their temperature through their heads, and covering them can lead to dangerous overheating.

The Ultimate Dressing Chart

For quick reference, here’s a handy table to help you decide. Pin this, screenshot it, or stick it on the fridge!

Even with the perfect chart, every baby is different. It’s essential to learn your baby’s unique cues. After you’ve put them down for a bit, do a quick check. Trust your parental instincts—they are powerful!

Signs Your Baby May Be Too Hot:

• Sweaty neck, back, or chest
• Flushed, red cheeks
• Rapid breathing or an increased heart rate
• Restlessness or fussiness
• Heat rash (small red bumps)

If you notice these signs, remove a layer of clothing immediately. You can also offer some breastmilk or formula, as dehydration can accompany overheating.

Signs Your Baby May Be Too Cold:

• Neck or torso feels cool to the touch (remember, hands and feet aren’t reliable indicators)
• Becoming unusually lethargic or difficult to wake
• Unusual fussiness

If your baby feels cool, don’t panic. Simply add another light layer, like a long-sleeve onesie under their sleep sack, or switch to a sleep sack with a slightly higher TOG rating for the next nap. It’s always safer for a baby to be slightly cool rather than too warm.