New parents often worry more about their baby being too cold than too warm—but overheating is actually the bigger concern, especially during sleep. The good news: it's easy to check for and easy to fix once you know the signs. Here's what to look for, and what to do about it.
Why overheating matters
Babies can't regulate their body temperature as efficiently as adults, and overheating during sleep is a recognized risk factor pediatric guidelines take seriously. The fix isn't complicated: dress in appropriate layers, keep the room at a comfortable temperature, and know how to check. It's far more about awareness than anything technical.
How to actually check: the back of the neck (not the hands)
Here's the single most useful tip: check the back of your baby's neck or their chest, not their hands or feet. Babies' extremities are often cool or slightly cold even when the rest of them is perfectly warm—that's normal circulation, not a sign of cold. The neck and chest give a true reading.
- Warm and dry: just right.
- Hot and sweaty: overheating—remove a layer.
- Cool: add a layer, but check again in a few minutes before assuming they're cold.
Other signs of overheating
Beyond the neck check, watch for:
- Flushed or red skin, especially on the cheeks or chest.
- Sweating, particularly around the hairline or back.
- Rapid breathing or unusual fussiness that doesn't settle with feeding or comfort.
- Heat rash—small red bumps, often in skin folds or under clothing.
- Damp hair or clothing when you check on them.
Common causes of overheating
- Too many layers for the room temperature—the classic "one more layer than an adult" rule is a guide, not a rule to stack endlessly.
- Synthetic fabrics that trap heat instead of breathing. Natural fibres like cotton and linen let heat escape.
- A hat left on indoors or during sleep—hats are for going outside or cold rooms, not everyday wear at a comfortable temperature.
- A room that's too warm. Pediatric guidance generally points to a comfortable, moderate room temperature rather than a warm one—use a room thermometer if you're unsure.
- Loose blankets instead of a sleep sack, which can bunch up and trap heat unevenly.
What to do if your baby feels overheated
- Remove a layer right away.
- Move to a cooler room if possible, or adjust the thermostat.
- Offer a feed if it's been a while—mild dehydration can add to discomfort.
- Recheck the back of the neck in a few minutes to confirm they've cooled down.
If your baby seems unusually unwell, very lethargic, or the overheating doesn't improve, contact your pediatrician—this guide covers everyday overdressing, not a medical emergency.
Prevention is simple
Choose breathable natural fabrics, dress by room temperature rather than the calendar, and do a quick neck check whenever you're unsure. For more on getting the layering right in every season, see our guide on how to layer baby clothes by weather, and our tips on keeping baby warm at night safely for the sleep-specific version of this same check.
The takeaway
Overheating shows up as a hot, sweaty neck or chest, flushed skin, or heat rash—not cold hands, which are normal. Dress in breathable layers appropriate to room temperature, skip the hat indoors, and check the back of the neck whenever you're unsure. It's a simple habit that keeps your baby comfortable and safe. For soft, breathable everyday basics, browse our organic cotton baby clothes.