As a pediatric sleep educator, I am often asked how to dress a baby for safe and comfortable sleep. New parents hear so much advice about feeding and postpartum recovery, but clothing and temperature are rarely discussed. When I brought home my first baby, all I knew was to keep her warm and swaddled. I had no idea there was an entire world of sleep sacks, TOG ratings, and temperature guidelines that actually support safer sleep.
Six years later, after extensive sleep education, I now know how important this overlooked topic is. Here is what every parent should understand about dressing their baby appropriately for safe sleep.
Related: Swaddles and Sleep Sacks: Safety Tips and What to Keep In Mind
Best Room Environment and Temperature for Safe Sleep
Let’s start with the room environment and temperature. The best temperature for sleep in a nursery found in most studies is 68-72ºF for both optimal and safe sleep.1 It may seem a little chilly, but our body temperature naturally drops at night. Maintaining a cooler environment allows your body to remain in its natural sleep cycle.
Studies have shown that sleeping in a room above 70°F can trigger the slow production of melatonin, our natural sleep hormone.2 Keeping the temperature cooler allows for more time for deep sleep. While parents often worry about their babies being too cold at night, studies have found that going to bed too warm can have an impact on sleep safety.3 These studies also indicate that having a child who is too warm or going to bed overheated is linked to an increased risk of sudden infant death syndrome (SIDS).
Related: How to Swaddle a Baby
Dress Your Baby Based on Room Feel and Season
But what about when 70° feels different during different seasons? The American Academy of Pediatrics (AAP) doesn’t suggest specific temperature ranges to account for these variances. Instead, they recommend dressing your baby appropriately based on the feel. For example, if it “feels” much like 70°, you will want to consider a long-sleeved sleeper and a sleep sack.
Understanding TOG Ratings for Sleep Sacks
Your sleep sack will have a TOG rating or a Thermal Overall Grade, a unit of measure ranging from 0.5 to 3.5, indicating the level of insulation. The TOG rating correlates with the temperature for which that sleep sack is best suited. For example:
- 0.5 TOG is optimal for 74-78°F and is typically made from cotton muslin
- 1.0 TOG rating is perfect for 70-72°F
- 1.5 TOG rating is appropriate for 68-69°F
- 2.5 TOG is most appropriate for winter weather of 64-68°F — you will find these made of fleece or even a down material
As a pediatric sleep educator, I often see parents gain confidence once they understand how TOG ratings match with room temperature.
How to Safely Check Your Baby’s Temperature and Comfort
Now, what do you do under that sleep sack? The best rule of thumb for dressing your baby at night with a sleep sack is to add a layer to what you’re wearing. For example, if you have light layers, consider opting for lightweight, organic sleeveless onesies.
In these room temperatures, however, it’s always best to check your child’s temperature for comfort by checking the back of their neck or chest to determine if they need more layers. Checking your baby’s hands or feet is not a reliable way to gauge their temperature, since they are often naturally cool. A better measure is the back of the neck or chest.
Related: How to Take a Baby’s Temperature
How to Transition Your Baby Out of the Swaddle
When determining your sleep sack or swaddle, remember to transition out of that swaddle by eight weeks. This transition time is because most babies will start developing signs of rolling and moving. You will notice that most swaddles will not have a TOG rating. These traditional swaddles include items such as muslin blankets. In these cases, you will want to use your child’s core to determine comfort at night and to dress your baby for safe sleep.
If your child seems too warm, or you find yourself in the hot summer months with limited control over air conditioning, consider adding a fan to your space. You can also put your child in a onesie instead of a long-sleeved sleeper. If your child is older than eight weeks, it’s time to consider a transitional swaddle or sleep sack, which will likely have various TOG ratings to match your environment.
Related: When to Stop Swaddling Your Baby (and How to Transition)
A transitional swaddle can be great for the change from a full swaddle to a sleep sack. If you live in a warm area, consider a shirt-only or short-sleeved onesie. If you are in a much colder area, consider doubling up on the onesie. Remember, however, cool is best for your little one!
Dressing your baby safely for sleep does not need to be complicated. By understanding room temperature, TOG ratings, and how to check for comfort, you can help your little one sleep safely and soundly. Trust your instincts, keep the environment cool, and choose sleepwear that supports your baby’s stage of development. Small adjustments can make sleep safer and more restful for the whole family.
