How should a 1 month old baby be dressed at night?

The basic principle for dressing a 1-month-old at night is: don't dress your baby in one more layer than you're comfortable wearing. If the room is around 20-22 degrees Celsius (ideal room temperature), a thin cotton onesie with a sleep sack or quilted sleeper (for example, a 2.5 TOG rated sleep sack) is enough. Babies lose heat very quickly through their heads, so a thin cotton cap or a sleep sack that doesn't cover the head is sometimes preferred.

Don't worry about cold hands — babies' hands are naturally cool due to circulation. What you should check is the back of the neck: if it's warm and sweaty, your baby is overdressed; if it's cool, they're unlikely to be cold. Never use a thick blanket or quilt covering your baby's head — this increases the risk of sudden infant death syndrome (SIDS). For safe sleep, always place baby on their back, face exposed, on a firm mattress.