What Should a 3–6 Month Old Wear to Bed at 25°C?

Why this combination works at 25°C

25°C is the first temperature in this guide where the question shifts from how to keep baby warm to how to keep them from overheating. The 0.2 TOG sleeping bag is the lightest practical option on the Australian market — it adds almost no insulation, but it keeps the sleep surface clear and fitted, which matters for safe sleep under 12 months. A loose blanket at 25°C carries the same risk as a loose blanket at any temperature.

At 25°C, a short-sleeve cotton bodysuit under the 0.2 TOG bag lets skin breathe while still providing a layer between baby and the bag. The bag itself is doing less thermal work here and more structural work — keeping the sleeping environment uncluttered without adding heat. A 3–6 month old can't push off a cover that's too warm, which is exactly why the fitted bag still makes sense even in a warm room.

If your baby isn't showing rolling signs yet, a lightweight muslin swaddle is thermally comparable to the 0.2 TOG bag at 25°C — muslin is almost neutral in warm conditions and lets air circulate. Once any rolling signs appear, the fitted 0.2 TOG bag is the right call. Don't combine a muslin swaddle with a bag at this temperature — one or the other is enough.

Signs you've got it right (or wrong)

At 25°C, the touch test reads differently than in a cooler room. You're looking for: chest and back of the neck feel warm — not damp, not hot, and not clammy. Damp hair around the hairline or flushed cheeks are clear overheating signals; if you feel either, remove the bodysuit and try nappy-only under the 0.2 TOG bag, or check whether the room can be cooled before the next sleep.

In dry heat — Perth, inland NSW, the Riverina — sweat evaporates quickly, so the skin can feel fine even when baby is running warmer than ideal. In dry conditions, the touch test is less reliable than in humid air. A digital room thermometer alongside the chest check gives a clearer picture. If the room is holding at 25°C and the thermometer confirms it, the short-sleeve and 0.2 TOG bag is the right call — but check more frequently in the first few nights until you know how the room behaves.

Layering for 25°C in an Australian home

In concrete terms: a short-sleeve cotton or bamboo bodysuit under a 0.2 TOG sleeping bag. Cotton and bamboo are the right fabric at 25°C — polyester blends hold heat. The ergoPouch 0.2 TOG sleep suit or sleeping bag, the Love to Dream Swaddle UP 0.2 TOG, or a light cotton bodysuit paired with a Bubba Blue 0.2 TOG bag are standard summer options at Australian baby stores.

In Perth, reverse-cycle aircon is close to universal in newer homes and is typically set between 23–25°C overnight. If the aircon is set to 24°C in an adjacent room and the baby's door is partially closed, the baby's room may hold at 25°C depending on the layout and insulation — that's a normal Perth summer scenario, and the short-sleeve bodysuit and 0.2 TOG bag covers it. If the home is naturally ventilated with windows open, outdoor temperatures drop dramatically once the Fremantle Doctor arrives — but bedrooms retain daytime heat in walls and ceilings, so the room typically settles between 22–24°C overnight rather than matching the outdoor minimum. At those temperatures the short-sleeve bodysuit and 0.2 TOG bag is still the right combination. If the room does drop below 22°C, swapping to a long-sleeve bodysuit is an easy fix without changing the bag.

If you're using a fan at 25°C: position it to circulate air in the room, never pointed directly at the cot. A fan moving air around the room helps without the chilling effect of direct airflow on a baby who can't move away from it. Red Nose Australia notes that adequate room ventilation is generally helpful for safe sleep, while emphasising that appropriate room temperature is the priority — a fan is not a substitute for getting the room to the right temperature.

When room temperature shifts overnight

Perth and the south-west of WA have one of the largest diurnal temperature ranges of any Australian capital — summer days hit 38–40°C, and outdoor temperatures fall sharply once the Fremantle Doctor arrives in the evening. Bedrooms are slower to cool: walls and ceilings retain daytime heat, so a naturally-ventilated Perth bedroom typically settles between 22–24°C overnight, depending on insulation and construction type, rather than tracking the outdoor minimum. At those temperatures the 0.2 TOG bag and short-sleeve bodysuit remains the right call. If the room drops below 22°C — more likely in a lightly-built weatherboard than a brick veneer — swapping to a long-sleeve bodysuit under the same bag is a simple fix worth doing at the first night feed.

In an aircon-controlled Perth home, the room stabilises at the thermostat setting within an hour of the system running. If you've set the thermostat to 24°C, the room will settle close to that regardless of what happens outdoors overnight. In that scenario, the 0.2 TOG combination works through to morning without adjustment — and you won't need to check unless your AC is known to cycle off on a timer.

Frequently asked questions