Five points to avoiding overheating baby.

Overheating can increase the risk of cot death. Babies overheat when there is too much bedding or clothing, or the room is too warm. Remember that a folded blanket is as warm as two blankets.
Lightweight blankets make it easier to control the temperature.
When you check on your baby, if he or she is perspiring, or their tummy feels hot to the touch, remove a blanket. It is absolutely normal that an infant's hands and feet are cool.
Room temperature of 16 to 18degrees C (63-65 degrees F) is a comfortable temperature,
The easy way to get it right is;-

• In summer baby may only need a sheet if it is very warm. (19-22 degrees C)
• Even in winter, most babies who are unwell or feverish need fewer clothes.
• Excess heat is lost through babies head, which is why it should never be covered at bed time, unless the room is very cold.
• Always remove hats and extra clothing as soon as you come indoors, enter a warm car,bus or train, even if it means waking your baby.
• Babies should never sleep with a hot water bottle, electric blanket, next to a radiator or in direct sunshine.

During the day baby should have one more layer of clothing than you have on.