Generally speaking, a two-piece cotton PJ set or footed onesie plus a muslin swaddle should suffice. However, this rule is just the tip of the iceberg. You'll also need to judge if this generalization applies to your baby's sleeping environment.
If the room is slightly cooler (20 degrees), then baby should be in a 2.5 tog sleeping bag and wear a long-sleeved bodysuit. If the room is slightly cooler (18 degrees), then baby should be in a 2.5 tog and wear a long-sleeved body suit and pyjama top.
6 stretch suits (all-in-ones) for both day and night, or 4 stretch suits and 2 nightdresses (nighties) for the night – use socks or bootees with the nightie if it's cold. 2 cardigans, wool or cotton rather than nylon, and light rather than heavy – several light layers of clothing are best for keeping your baby warm.
A multi-layered approach
It's a good idea to check what you're wearing and put them in one more layer (American Academy of Pediatrics, 2016). So, if you're in a shirt, sweater and jacket, your baby might need a vest, sleepsuit, jumper and coat (plus hat and gloves as needed).
The easiest way to tell if your baby is too hot or too cold is by feeling the nape of the neck to see if it's sweaty or cold to the touch. When babies are too warm, they may have flushed cheeks and look like they're sweating. An overheated baby may also breathe rapidly.
The air in babe's room is too cold.
Even if babe is super warm, if they are breathing in cold air, it can wake them up. This is often the cause for early morning waking - as a baby who has gone to bed in a cold room wakes up as the temp drops suddenly in the early hours.
The risk for sudden infant death syndrome is higher during colder months, so parents and caregivers should be aware of this risk and take the necessary precautions, according to a press release from the NIH.
Too many layers, even in the winter, can lead to baby overheating in their sleep. Your house thermostat may not give an accurate reading for the room your child sleeps in, so you might consider using a baby monitor that measures room temperature.
In warmer weather, you can dress baby in a sleeveless and legless onesies, or just a nappy and singlet. For cooler weather, a full suit will keep baby warm. If you are using a sleeping bag, select the TOG that matches the temperature of the room.
You don't want your baby's room to be either too hot or too cold. It's recommended that the best temperature for babies is between 68 to 72 degrees Fahrenheit or 20 to 22 degrees Celsius. Babies are more sensitive to changes in room temperature because they're so small and their bodies are still growing.
Signs of hypothermia include shivering, breathing slowly and having pale, cool skin. Babies who are hot, tend to look uncomfortable. Like adults who overheat, a baby's skin will become red, and they will look flushed.
The best way to check if your little one is the correct temperature is to put your hand on the child's chest. Does their chest feel comfortable and warm? It should not be hot or cool to your touch. Touching your baby's hands and feet is not a good way to determine if your child is warm enough.
Here is a rough guide of how to safely dress your baby depending on the temperature: 27 degrees + – vest and nappy or nappy only. 24-27 degrees – short sleeved vest and 0.5 tog sleeping bag. 21-23 degrees – short or long sleeved vest and 1 tog sleeping bag.
Baby Sleeping Temperature Guide
As a general rule, if the room temperature is around 18-20 degrees Celsius, put your newborn or older baby to bed in a vest and bodysuit or gown.
As a guide, dress your baby in the same number of layers you're wearing, plus one extra layer for warmth. Although it's important to keep newborns warm, it's just as important that your baby doesn't overheat, especially during sleep.
Safe Sleep Guidelines for Your Baby
Anything that could potentially cover their mouth and nose could lead to suffocation for your infant. The American Association of Pediatrics (AAP) has issued safe sleep guidelines. This includes a strong recommendation against having blankets in your baby's crib.
On the warmer nights when it's between 21-24 degrees Celsius, they should be fine in a vest with short sleeves. When it's a cooler 18-21 degrees Celsius, they can wear a vest with short sleeves and short legs or a baby grow with feet.
Dress your baby in layers of fitted clothing rather than just thick pyjamas. You can add or take away layers as the temperature changes. Babies cool themselves down by releasing heat from their heads and faces. Babies can quickly overheat if they fall asleep wearing hats or beanies.
If the toes are a little cool, but not cold and the baby's belly is warm the baby is dressed warmly enough. But if the belly and the toes are both warm, the baby could be overdressed.
Make sure your baby is dressed appropriately for their environment and does not have too many layers on. According to the American Academy of Pediatrics (2016), an infant should not wear more than 1 layer more than what an adult would need to be comfortable in that same environment.
No matter the season, keep the room your baby is in between 68 to 72 degrees Fahrenheit (20 to 22.2 degrees Celsius). While you can measure the room temperature with a thermometer, in general, the temperature should not be too cool or too warm for an adult.
While the cause of SIDS is unknown, many clinicians and researchers believe that SIDS is associated with problems in the ability of the baby to arouse from sleep, to detect low levels of oxygen, or a buildup of carbon dioxide in the blood. When babies sleep face down, they may re-breathe exhaled carbon dioxide.
Most SIDS deaths happen in babies between 1 and 4 months old, and cases rise during cold weather. Babies might have a higher risk of SIDS if: their mother smoked, drank, or used drugs during pregnancy and after birth. their mother had poor prenatal care.