A 2.5 TOG sack over a long-sleeve bodysuit.
For a baby up to a year, in a 64°F room: long-sleeve bodysuit and sleep sack (2.5 TOG).
At 64°F the room is inside the range the safe-sleep charities recommend, and a 2.5 TOG sack over a long-sleeve bodysuit is the usual starting point.
The makers' charts give 2.5 TOG for a 61–68°F room. Baby Layers uses it from 64–68°F and adds a layer under it below that.
Nothing goes on top of the sack. It is the whole of the bedding.
A 2.5 TOG sack over a long-sleeve bodysuit for a room of 64–68°F.
64°F is inside the 61–68°F the Lullaby Trust recommends for a baby's room.
At 63°F it changes to long-sleeve bodysuit, sleepsuit and sleep sack, 2.5 TOG.
At 66°F the answer stays the same.
Every night, whatever the room: Never a hat for sleep — a baby cools through the head. A sleep sack, never a loose blanket. Safer slightly cool than too warm: nothing makes the sack warmer than the chart.
0–3 months: long-sleeve bodysuit and sleep sack (2.5 TOG). 3–6 months: long-sleeve bodysuit and sleep sack (2.5 TOG). 6–12 months: long-sleeve bodysuit and sleep sack (2.5 TOG). 1–3 years: long-sleeve bodysuit and sleep sack (2.5 TOG). 0–3 months, swaddled: long-sleeve bodysuit and swaddle.
Runs warm: the answer at 64°F stays the same.
Runs cool: asleep the app never goes warmer than the chart, so the answer stays the same. If the chest or neck feels cool, a layer under the sack helps.
Check the neck — warm but not sweaty means just right.