The recommended room temperature for a newborn is 16 to 20°C (roughly 61 to 68°F). Keeping the nursery within this range helps lower the risk of sudden infant death syndrome (SIDS) and supports your baby’s still-developing ability to regulate body heat. That range may feel slightly cool to you as an adult, and that’s perfectly fine.
Why Newborns Are So Sensitive to Temperature
Newborns lose heat quickly and have limited ability to protect themselves against that loss. Heat escapes through their skin via evaporation, direct contact with cool surfaces, radiated warmth leaving the body, and air moving over exposed skin. Adults compensate for cold by shivering, but newborns rely almost entirely on a special type of fat called brown fat to generate warmth. This process burns a lot of energy, and premature infants have even less capacity for it than full-term babies.
On the other end, babies can’t cool themselves efficiently either. Young infants don’t sweat much, so in a warm room they have no reliable way to bring their temperature down. This makes overheating a bigger concern than many parents realize.
The Link Between Overheating and SIDS
Overheating is recognized as a risk factor for SIDS. It can result from too many blankets, head covering that traps heat, or a bedroom that’s simply too warm. Research comparing SIDS cases across different outdoor temperatures found that the risk more than tripled when ambient temperatures reached 30°C (86°F) compared to 20°C (68°F). Even when a baby’s core temperature stays technically normal, the thermal stress of fighting to cool down can be dangerous.
If you leave heating on overnight, keep it set no higher than 20°C (68°F). A room that feels comfortable to a lightly dressed adult is usually warm enough for a baby who has one extra layer on.
How to Dress Your Baby for Sleep
The simplest rule: dress your baby in no more than one layer beyond what you’d wear to be comfortable in the same room. If you’re fine in a t-shirt, your baby needs a t-shirt plus a light sleep sack or swaddle, not three layers of fleece.
Sleep sacks and wearable blankets are rated by a unit called TOG, which measures thermal resistance. Higher TOG means more warmth. Here’s a practical guide:
- 0.2 TOG: best for rooms between 24 to 27°C (75 to 81°F)
- 1.0 TOG: best for rooms between 20 to 24°C (68 to 75°F)
- 2.5 TOG: best for rooms between 16 to 20°C (61 to 68°F)
- 3.5 TOG: best for rooms below 16°C (61°F)
If you’re unsure which TOG to pick, err on the lighter side. It’s easier to add a layer than to notice your baby has gotten too warm while sleeping.
How to Tell If Your Baby Is Too Hot or Too Cold
A room thermometer in the nursery is the most reliable tool, but your baby’s body gives you direct feedback too. Place your hand on their chest or the back of their neck. These areas reflect core temperature better than hands and feet, which tend to run cool in newborns regardless of room temperature.
Signs of overheating include skin that feels hot to the touch, flushed or red cheeks, damp hair, fussiness, rapid breathing, or unusual lethargy. Keep in mind that young babies can be dangerously warm without visibly sweating, so don’t rely on sweat alone as a signal. A normal body temperature for a baby is around 36.4°C (97.5°F). Anything at or above 38°C (100.4°F) is considered a fever and warrants attention.
If your baby feels cold on the chest, they likely need an additional layer or a warmer sleep sack. Cold hands alone aren’t a reliable indicator.
Using a Fan in the Nursery
Running a fan in a baby’s sleep space may do more than keep air moving. A study published in JAMA Pediatrics found that fan use during sleep was associated with a 72% reduction in SIDS risk. The likely mechanism is simple: a fan prevents carbon dioxide from pooling around a sleeping baby’s nose and mouth, reducing the chance of rebreathing stale air.
The protective effect was strongest in warmer rooms, where fan use was linked to a 94% reduction in risk compared to a more modest effect in cooler rooms. A ceiling fan or a small oscillating fan placed away from the crib (never blowing directly on the baby) can help regulate both temperature and air quality. This is especially useful in summer months or if you can’t get the room below 20°C.
Humidity Matters Too
Temperature is only part of the equation. The ideal humidity for a nursery is between 35 and 50 percent. Air that’s too dry can irritate your baby’s nasal passages and make breathing harder, while air that’s too humid promotes mold growth and can also cause respiratory discomfort. A simple hygrometer (often built into nursery thermometers) lets you monitor both numbers at a glance. In dry winter months, a cool-mist humidifier can help. In humid summers, air conditioning or a dehumidifier keeps things in range.
Keeping the Nursery Stable Across Seasons
The trickiest part of maintaining 16 to 20°C isn’t knowing the number. It’s dealing with weather swings. In winter, heating can push a closed nursery well above the target range, especially overnight. Set your thermostat to 20°C or below and crack a door if needed to prevent heat buildup. Thermal curtains help block heat loss through windows without raising room temperature unevenly.
In summer, direct sunlight through a window can turn a nursery into the warmest room in the house. Cellular shades or blackout curtains block solar heat gain during the day. If you don’t have air conditioning, a fan becomes essential, both for cooling and for the air circulation benefits described above. During heat waves or cold snaps, check the nursery temperature more frequently, especially during nighttime hours when you’re less likely to notice a shift. A smart thermometer that sends alerts to your phone when the room drifts outside your target range can be worth the investment during a baby’s first year.
If you use a portable heater as a backup in cold weather, keep it well away from the crib, any fabric, and anything flammable, and never leave it running unattended in the nursery overnight.