The best place to check is the back of the neck or the chest, not the hands or feet. A baby's hands and feet run cooler than the rest of the body, so they can feel chilly even when your baby is warm enough, or even too warm. If the neck or chest feels damp, sweaty, or hot to the touch, your baby is dressed too warmly. Flushed cheeks and damp hair at the neckline are other signs, and a baby who's unusually fussy or restless may be too warm as well.
A simple rule of thumb: dress your baby in about one layer more than you'd wear yourself in the same room, not two or three. Fabric matters too. Muslin cotton is woven in an open, loose weave, so the gaps let air move through instead of trapping heat against the skin. Our clothes are double-layer muslin cotton, which gives some warmth without the bulk of thicker fabrics, and every piece is pre-washed so it's already soft against your baby's skin.
If your baby feels overheated, remove a layer and check the back of the neck again a few minutes later. This matters most during sleep, when a baby can't easily signal that they're too hot. Dress for the room they're actually in, not the season on the calendar: a heated house in winter or an air-conditioned room in summer often calls for lighter layers than the weather outside suggests.