The recommended room temperature for a newborn is between 68 and 72°F (20 to 22°C). This range keeps your baby comfortable during sleep and daily activity while reducing the risk of overheating, which is a known risk factor for Sudden Infant Death Syndrome (SIDS).
Why This Temperature Range Matters
Newborns can’t regulate their body temperature the way adults can. For roughly the first six months of life, babies rely on a special type of fat called brown fat to generate heat. This tissue burns energy and releases it directly as warmth rather than storing it. It’s an effective system for short bursts of warming, but it has real limits. Babies can’t shiver to produce heat, and they’re poor at constricting blood vessels near the skin to hold warmth in.
On the flip side, babies also struggle to cool themselves down. One of the main ways infants release excess heat is through their face. This is part of why back sleeping is so important: stomach sleeping blocks that heat release and can lead to dangerous overheating. A room kept between 68 and 72°F gives your baby a neutral environment where their body doesn’t have to work hard in either direction.
Overheating and SIDS Risk
Overheating is consistently linked to a higher risk of SIDS. Research from the University of Alabama at Birmingham found that elevated temperatures trigger stress-responsive genes in infant tissue cells, with two genes in particular showing significantly increased activity at higher temperatures. While the exact mechanism is still being studied, the practical takeaway is straightforward: keeping your baby’s sleep environment cool is one of the most important things you can do.
This means avoiding heavy blankets, excessive layers, and hats during sleep. It also means paying attention to airflow. Running a ceiling fan or providing gentle air circulation in the nursery has been associated with reduced SIDS risk.
How to Tell If Your Baby Is Too Hot or Too Cold
A room thermometer is helpful, but your baby’s body gives you the most reliable feedback. The best place to check is the back of the neck or the chest. If the skin there feels hot, sweaty, or clammy, your baby is too warm. If it feels cool to the touch, they need another layer.
Signs of overheating include:
- Flushed or red skin
- Damp hair or sweating (though babies can overheat without visible sweat)
- Fussiness or restlessness
- Rapid heart rate
- Unusual sleepiness or sluggishness
Cold hands and feet alone aren’t cause for alarm. Newborns naturally have cooler extremities because their circulatory system is still maturing. Focus on the torso and neck as your guide.
Dressing Your Baby for Sleep
The general rule is to dress your baby in one layer more than you’d wear comfortably in the same room. Sleep sacks are a safe alternative to loose blankets and come rated by a system called TOG, which measures insulation. The lower the TOG number, the lighter the fabric.
A simple guide based on room temperature:
- Above 71°F: A lightweight sleep sack (0.2 to 0.3 TOG) or just a onesie
- 67 to 75°F: A mid-weight sleep sack (1.0 TOG) with a bodysuit underneath
- 59 to 69°F: A warmer sleep sack (2.5 TOG) with a long-sleeved bodysuit
- Below 65°F: The warmest sleep sack (3.5 TOG) with heavier pajamas underneath
These are starting points. Some babies run warmer or cooler than average, so check their chest and neck regularly and adjust. If your baby is sick or has a fever, drop down a layer since their body is already producing extra heat.
Humidity and Air Quality
Temperature is only part of the equation. Boston Children’s Hospital recommends keeping indoor humidity between 35 and 50 percent. Air that’s too dry can irritate your baby’s nasal passages and skin, while air that’s too humid encourages mold growth and can make breathing harder. A simple hygrometer (available for a few dollars at any hardware store) can sit in the nursery alongside your thermometer.
If your home runs dry, especially in winter with forced-air heating, a cool-mist humidifier can bring levels up. If humidity creeps above 50 percent in summer, a dehumidifier or air conditioning helps bring it back in range.
Practical Tips for Maintaining Temperature
Keeping a consistent 68 to 72°F sounds simple, but nurseries can be tricky. Rooms on upper floors tend to run warmer. Rooms with large windows can swing with outdoor temperatures. A few adjustments make a big difference.
Place your baby’s crib away from windows, exterior walls, heating vents, and direct sunlight. These are all sources of temperature fluctuation that a room thermometer on the opposite wall won’t catch. A small digital thermometer near the crib gives you the most accurate reading of what your baby actually experiences.
In summer, air conditioning or a fan pointed away from the crib (not directly on your baby) keeps air moving without creating a draft. In winter, resist the urge to crank the heat in the nursery. If the room feels slightly cool to you in a t-shirt, it’s likely perfect for a swaddled or sleep-sacked baby. Footed pajamas plus a mid-weight sleep sack handle most cold-weather nights without needing to raise the thermostat above 72°F.