Comfortable room — a light top and socks.
For a baby of 6–12 months, awake, in a 21°C (70°F) room: short-sleeve bodysuit and socks.
Short sleeves from 21°C, covered arms below.
Socks below 24°C, warm ones below 15°C.
0–3 months: long-sleeve bodysuit, pants and socks. 3–6 months: long-sleeve bodysuit, pants and socks. 6–12 months: short-sleeve bodysuit and socks. 1–3 years: T-shirt and socks.
At 20°C it changes to long-sleeve bodysuit, pants and socks.
At 22°C the answer stays the same.
Runs cool: the app dresses a touch warmer, long-sleeve bodysuit, pants and socks.
For sleep in the same room, the app suggests short-sleeve bodysuit, in a 1.0 TOG sack.
No hat indoors — a baby cools through the head.
Check the neck — warm but not sweaty means just right.