Mild days are the light-sweater range: covered arms below 20°C, a light knit or cardigan below 19°C, soft trousers and cotton socks.
For a baby of 6–12 months on a still, dry day:
19°C (66°F): long-sleeve bodysuit, pants and socks. Mild — add a light mid layer. 15–18°C (59–64°F): long-sleeve bodysuit, pants, socks and light sweater. Mild — add a light mid layer. 14°C (57°F): long-sleeve bodysuit, pants, socks, light sweater and warm hat. Mild — add a light mid layer.
The warm hat comes off from 15°C. A newborn, who is dressed as if it were a little colder, keeps it a degree or two longer, as the age table below shows.
The easiest layer to lose is the sweater. If the neck feels sweaty after a while in the sun or a warm shop, that is the one to take off.
Each piece comes on at its own temperature, a degree or two apart, so the outfit changes one piece at a time.
One light layer from 20°C, covered arms below.
Pants below 25°C (toddlers keep shorts to 21°C), lined ones below 13°C.
Socks below 24°C, warm ones below 12°C.
A sweater below 19°C, a warm one below 14°C.
A warm hat outdoors below 15°C.
0–3 months, 16°C: long-sleeve bodysuit, pants, socks, light sweater and warm hat. 3–6 months, 16°C: long-sleeve bodysuit, pants, socks and light sweater. 6–12 months, 16°C: long-sleeve bodysuit, pants, socks and light sweater. 1–3 years, 16°C: long-sleeve bodysuit, pants, socks and light sweater.
Still and dry: Mild — add a light mid layer. Windy (feels like 13°C (55°F)): Adds warm sweater and warm hat. Drops light sweater Raining (feels like 15°C (59°F)): Adds jacket Sunny (feels like 18°C (64°F)): No change In a carrier (your warmth counts on the body): Drops light sweater In a car seat (no coat under the straps): No change
Indoors, or in a warm car, bus or train, take the hat and outer layers off.
Check the neck — warm but not sweaty means just right.