It depends on where it's coming from. There is no cooling system connected to most cold water taps, so the temperature never drops below that of the source.
It's easy.Boil it. You will need to have the particles gain kinetic energy so they move around faster, and that will make the liquid warmer.
Lack of heat energy in the surrounding area to warm it up.
Its just like taking a bubble bath in your tub but without the bubbles. You should probably go on a hot day.
Hot water is less denser than cold water and has a greater temperature.