Many times we touch our baby's feet or hands and they are cold, so we assume that our baby is cold and this is not always the case. This is because a newborn does not yet have a fully developed blood system.
If you want to know when a baby is hot or cold, you should touch his legs, arms or neck, since that is where the baby's temperature is felt.
If it is cold, ideally you should put several pieces of clothing that are not very thick instead of a single very warm piece. In case it is hot, you can remove some garment without undressing it too much. If it is hot you should not take it out almost without clothes, it is better to always have warm clothes on hand, since weather changes may cool.