The temperature of water is cooler in deep oceans. The temperature there goes to 0°C to -3°C below which the water freezes. The water on the surface of the oceans and deep inside it varies because of the difference in energy of the two layers. One of the widest use of cold water is air conditioning. Cold water has a higher density than warm water. Water gets colder with profundity since chilly, salty sea water sinks to the base of the sea beds underneath the less dense hotter water close to the surface.