If your mom is anything like mine, she insists that your baby be covered from head to toe – outfit, hat, mittens, socks, blanket – anytime you leave the house or set the air conditioner lower than 80 degrees. This was a regular discussion we had, as I was pretty good at figuring out how to dress my baby during waking hours. But, even though I wouldn't admit it to my mom, night time had me stumped. They aren't supposed to sleep with blankets, so how many layers should a baby sleep in in order to stay warm enough or cool enough?
According to Baby Sleep Site, swaddled babies should wear a onesie under a light long-sleeved sleeper, plus socks in the winter. In the summer, swaddled babies can skip the socks and switch to a short-sleeved sleeper. Once your baby grows out of being swaddled, the outfit can stay the same, but the blanket should be replaced by a sleep sack. The number of layers you should put on your baby, of course, depends on the room temperature and not just the season. With the use of an air conditioner or a heater the indoor temperatures can get much too cool in the summer to be without socks or much too warm in the winter to wear a footed sleeper.
Certified Infant & Child Sleep consultant, Pam Edwards has a handy chart on her site Wee Bee Dreaming Pediatric Sleep Consulting that outlines room temperatures and the corresponding clothing a baby should wear. Edwards noted that the optimal room temperature for a baby to get good-quality sleep is between 68 and 72 degrees Fahrenheit.
The number of layers a baby in a sleep sack should wear also depends on its tog rating. According to Slumber Safe, the tog rating of a sleep sack determines its thickness and therefore how warm it keeps your child. The warmest sleep sacks have the highest tog ratings.
It's important to check your baby regularly to make sure they don't overheat. Slumber Safe recommended feeling the nape of your baby’s neck. If it is damp or sweaty then your baby is too warm. Over bundling can increase a baby's risk for SIDS, according to the National Institutes of Health.