Ask half the women if you should wash your face in warm water, and they will tell you "yes". Ask the other half, and they'll probably tell you "no", that it is best to wash your face in cold water. So what is it? Warm or cold?
The preferred temperature is lukewarm water (not too hot, but not too cold). Lukewarm water opens the pores of the skin which allows the facial cleanser to get in there to remove makeup and grime.
However, for rinsing the face, it is better to splash cold water on the skin. Cold water closes up the pores of the skin.