Cool hands are normal — check the chest and neck instead.
Little hands and feet often run cool even when a baby is perfectly comfortable. Warm, dry skin on the chest or back of the neck is the reassuring sign.
Cool chest or tummy Cool back of the neck
If the chest feels cool, add one thin layer and check again. Cool hands alone are usually nothing to worry about.
Outside in the cold
The NHS and the American Academy of Pediatrics both suggest one more layer than you would wear yourself. Several thin layers keep the warmth in better than one thick one, and a hat and mittens go on outdoors in the cold.
Newborns hold heat less well, so the app dresses them as if it were a little colder, easing off by six months.
At night
In a cool bedroom, a layer under the sleep sack is what helps, never a blanket on top of it. Below 18°C (64°F) the app adds a sleepsuit under the 2.5 TOG sack.
Keep added heat away from the cot: no hot-water bottle or electric blanket, and not next to a radiator, heater or fire.