Does fire go out faster with hot water or cold water?

Answer 1

I'd think: faster with cold water because the temperature fall is quicker and that is the main reason for the good extinguishing power of water -besides of being not burnable itself, of coarse-.

It depends on the type of fire. On some fires such as an electrical fire, you would not want to use water at all.

Added:

Discussion: The first part of the last paragraph is very correct, but I don't know what "electrical fire" is.

(Can electricity burn, not being a substance?; it can be a main cause of fire though, but fire needs more than a cause, eg. burnables and oxygen)

A better example of a fire not to be extinguished with water is burning oil or fat or other immiscible volatile organic fluid.

An Electrical Fire is a Class C Fire. Check USCG regulations.