A room temperature of 73°F (22.8°C) is above the recommended range for a baby’s sleep environment. Most safe sleep guidelines recommend keeping a baby’s room between 61°F and 68°F (16–20°C), which means 73°F is roughly 5 degrees warmer than the upper limit. That doesn’t make it dangerous on its own, but it does increase the risk of overheating, especially depending on how your baby is dressed and what bedding you’re using.
What the Guidelines Actually Recommend
The Lullaby Trust, one of the leading authorities on infant sleep safety, recommends a room temperature between 16 and 20°C (61–68°F) to reduce the risk of sudden infant death syndrome (SIDS). Their guidance is clear that heating should be set “certainly no higher than 20°C.” At 73°F, you’re sitting about 3°C above that ceiling.
That range feels surprisingly cool to most adults, which is why so many parents end up searching this question. The instinct to keep a baby warm is strong, but babies are actually more vulnerable to overheating than to being slightly cool. The ideal is a room that feels comfortable to a lightly dressed adult, not one that feels cozy or warm.
Why Overheating Matters for Babies
Babies can’t regulate their body temperature the way adults can. They have a higher body surface area relative to their size, which means they absorb heat from the environment faster. Their sweating response is less developed, their metabolic rate is higher, and they have a smaller blood volume to help distribute and dissipate heat. All of this means a room that feels fine to you can genuinely stress your baby’s system.
Thermal stress during sleep is one of the known risk factors for SIDS. When a baby gets too warm, it can impair their ability to wake up, disrupt normal breathing patterns, and affect how well oxygen reaches the brain. Research published in a large U.S. study found that a 10°F increase in daily temperature during summer months was associated with an 8.6% increase in SIDS risk. The effect was even more pronounced in babies older than 2 months, where the increased risk reached nearly 17% per 10°F rise. Overheating doesn’t cause SIDS on its own, but it compounds other risk factors like heavy swaddling or prone sleeping.
How to Tell If Your Baby Is Too Warm
A room thermometer is the most reliable tool, but your baby will also give you physical cues. The best spot to check is the back of the neck or the chest. If the skin there feels hot or damp, your baby is likely too warm. Other signs include:
- Flushed or red skin
- Sweating or damp hair (though babies can overheat without sweating)
- Fussiness or restlessness during sleep
- Rapid heart rate
- Unusual sluggishness or limpness
Cold hands and feet alone don’t mean your baby needs a warmer room. Babies commonly have cool extremities even when their core temperature is perfectly fine. Always check the chest or neck rather than the fingers or toes.
Making 73°F Safer When You Can’t Cool the Room
Keeping a room at 68°F isn’t always realistic, especially during summer or in homes without air conditioning. The Lullaby Trust acknowledges this directly, noting that maintaining the ideal range in warmer months can be genuinely difficult. If you’re stuck at 73°F or above, there are practical steps that make a real difference.
The single most impactful thing you can do is use a fan. A study published in JAMA Pediatrics found that fan use during sleep in rooms warmer than 70°F (21°C) was associated with a 94% reduction in SIDS risk. The effect likely comes from moving air around the baby’s face, which prevents carbon dioxide from pooling near the nose and mouth. In cooler rooms, fan use didn’t show a significant benefit, suggesting it’s specifically helpful when temperatures climb above the recommended range.
Dress your baby lighter when the room is warm. At 73°F, a single layer (a short-sleeve bodysuit or a lightweight sleep sack with a TOG rating of 0.5 or lower) is typically enough. Skip blankets entirely. If you’re using a swaddle, make sure it’s a thin, breathable fabric rather than a thick fleece. Every additional layer traps heat against your baby’s body.
Open a window if outdoor conditions and safety allow it. Ventilated bedrooms are associated with lower SIDS risk independent of temperature. Even a small amount of airflow helps. If you have blackout curtains or blinds, close them during the day to keep solar heat from building up in the nursery.
What Temperature Is Actually Dangerous
There’s no single degree at which a baby’s room becomes unsafe. Risk exists on a spectrum, and it depends on the combination of room temperature, clothing, bedding, and airflow. A baby in a warm fleece sleep sack at 73°F is at much higher risk of overheating than a baby in a diaper and light cotton at 75°F with a fan running.
That said, rooms consistently above 75°F (24°C) with no ventilation and standard sleep clothing should be treated as a priority to address. The further above 68°F you go, the more important it becomes to compensate with lighter clothing and air circulation. At 73°F, you’re in a manageable zone as long as you’re making those adjustments. At 80°F with no fan and a swaddled baby, the risk profile changes significantly.
If your home regularly stays warm overnight, a simple room thermometer placed near the crib (not in direct sunlight or near a vent) gives you a reliable number to work with rather than guessing.