Room temperature affects both the safety and quality of infant sleep. The range 16–20°C is a small one for a reason — both overheating and significant cold have negative effects. Understanding how to achieve and monitor this range, in different seasons and housing types, is practically useful.
Healthbooq provides evidence-grounded sleep environment guidance for every season and setting.
Why 16–20°C
Overheating and SIDS. Overheating has been identified as a risk factor for SIDS. The exact mechanism is unclear but likely involves impaired arousal response — similar to the prone sleeping mechanism. Infants who are too warm may be less able to arouse themselves from deep sleep when needed.
Sleep architecture and temperature. Core body temperature naturally drops as part of the sleep-onset process. A room that is too warm impedes this drop, potentially delaying sleep onset and producing lighter sleep. A room in the 16–20°C range supports the natural body temperature drop without causing cold discomfort.
How to Achieve the Right Temperature
- Thermometer: a room thermometer placed at baby's level is more accurate than the room's thermostat (thermostats typically measure at adult head height)
- Summer: a fan circulating air (not directed at the baby) can maintain a suitable temperature; open windows in cooler evening air; avoid direct sun on the sleep space
- Winter: maintain consistent central heating rather than allowing the room to cool significantly overnight; check for draughts near the cot
Checking Comfort by Touch
An environmental thermometer tells you the room temperature; it does not tell you how the baby is dressed for it. The most reliable comfort check is to place a hand on the baby's:
- Chest or abdomen: should be warm and dry
- Back of the neck: should be warm and dry
If the chest or neck is hot or sweaty, the baby is too warm — remove a layer or lower the room temperature.
Cold hands and feet are normal and do not indicate the baby is too cold — peripheral circulation is less developed in infants.
Sleep Sack Tog Ratings
Infant sleep sacks are rated in togs (a measure of insulation). Matching the tog rating to the room temperature is important:
- Below 16°C: 2.5 tog
- 16–20°C: 1.0–2.5 tog (lighter toward the warmer end)
- 20–24°C: 0.5–1.0 tog
- Above 24°C: 0.5 tog or lighter; fewer clothing layers underneath
Key Takeaways
Room temperature is a significant variable in infant sleep quality and safety. The recommended range is 16–20°C (61–68°F). Temperatures above this range are associated with increased SIDS risk and lighter, more fragmented sleep. Temperatures significantly below this range may cause discomfort that disrupts sleep. Checking the infant's chest temperature — not the environmental thermometer alone — is the most reliable indicator of thermal comfort.
