What Should a 3–6 Month Old Wear to Bed at 16°C?

What makes 16°C a boundary temperature

16°C is the warmest temperature that still calls for a 3.5 TOG sleeping bag — one degree warmer and the recommendation steps down to 2.5 TOG. It's also the floor of the 16–20°C range that Red Nose Australia identifies as appropriate for safe baby sleep: at 16°C you're within the recommended range, unlike at 15°C where the primary answer is to warm the room. The 3.5 TOG bag here isn't a maximum-effort response to a dangerously cold room — it's the calculator's precautionary answer for a room at the cool edge of the safe range that's likely to drift colder overnight.

For a 3–6 month old, the full combination is a long-sleeve cotton bodysuit, a footed sleepsuit, and a 3.5 TOG sleeping bag. If your room reliably holds at 17°C or warmer overnight — whether by heating or good insulation — the 2.5 TOG recommendation at 18°C may be more appropriate. At 16°C with no overnight heating, the 3.5 TOG combination is the right starting point.

The rolling note still applies at this age: many babies show rolling signs by 4–5 months, which means the fitted sleeping bag is the right call over a swaddle. A well-fitted 3.5 TOG bag moves with the baby safely. If your baby is not yet rolling, a warm swaddle is still appropriate at 16°C but the thermal difference between a swaddle and the 3.5 TOG bag is more meaningful at this temperature — the bag is the safer and warmer option.

Signs you've got it right (or wrong)

At 16°C, chilling is the more likely risk. Check the chest and back of the neck — warm to the touch is what you're looking for. A cool chest at this temperature is worth acting on promptly: check the room temperature first. If it's dropped to 14°C or below, the 3.5 TOG bag is doing its full job but the room has moved into territory where heating becomes important. Hands and feet run cool in any well-regulated baby, so ignore those.

Overheating is less likely at 16°C, but can happen if a portable heater warms the room significantly during the night — particularly if the room climbs above 18–19°C while baby is in a 3.5 TOG bag. If you notice damp hair around the hairline or flushed cheeks in a room that's warmed up, drop to a 2.5 TOG bag for the next sleep. Having a 2.5 TOG bag accessible is practical in any home where the bedroom temperature is variable.

Layering for 16°C in an Australian home

In concrete terms: a long-sleeve cotton bodysuit as the base layer, a footed sleepsuit over that, then a 3.5 TOG sleeping bag. The ergoPouch 3.5 TOG sleeping bag or cocoon is the most widely available option in Australian stores. Natural fibres — cotton, bamboo, merino — regulate temperature better than polyester in a cold room, so check fabric labels when buying layers.

In the Adelaide Hills — Stirling, Crafers, Aldgate, and the wider Mt Lofty Ranges — winter bedroom temperatures of 16°C are common, and the elevation adds 2–4°C of chill compared to Adelaide CBD. Many of the Hills' older brick homes from the 1950s and 1960s have limited insulation and no central heating: the reverse-cycle in the living area doesn't carry through to bedrooms. If you're in an unheated Hills bedroom at 16°C, the room will typically drift lower through the night. The 3.5 TOG combination is right for this scenario — it's rated for the 16°C starting temperature and provides a buffer as the room cools.

When room temperature shifts overnight

In the Adelaide Hills in winter, a 16°C bedroom at 7pm is often the warmest it will be that night. Without bedroom heating, temperatures in the ranges can fall to 13–14°C by pre-dawn — particularly in older homes that lose heat steadily, and in elevated suburbs like Stirling where cold air pools overnight. At that point, the 3.5 TOG bag continues to be the right choice, and the room has moved into territory where the 15°C guidance applies: heating the bedroom toward 18°C, if practical, is worth considering for the next sleep.

If your room instead holds at 16°C all night — good insulation, or passive warmth from adjacent living areas — the 3.5 TOG bag and full layering may run slightly warm by morning. Check the chest at the first night feed: if it's damp, the room is warmer than you thought and a 2.5 TOG bag on the next sleep may be more comfortable. Knowing what your home actually does overnight takes about a week of observation and a cheap room thermometer.

Frequently asked questions

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• What a 3–6 month old should wear at 15°C