Water temperature is all about preference... There hasn't been any proof that the temperature of the water has any affect of bacteria removal...
TODAY.com explained, “Water works as a physical cleanser and washes the organisms and microbes off the hands,” said Dr. Raymond Pontzer, director of infection prevention for UPMC in Pittsburgh, who was not involved in the study. “There is no evidence — and this study reinforces that — that the actual temperature of the water has anything to do with the antimicrobial properties of hand washing.”
But this is the correct way to wash your hands:
1. Wash your hands for at least 20 seconds, a good rule is to sing 'Happy Birthday' all the way through.
2. Lather with soap
3. Dry with a paper towel (the air dryers have been found to be less effective and leaves bacteria on your hands)
4. Use the temp YOU prefer, what ever is most comfortable.
5. Moisturize the more cracked or dry your hands are the more bacteria
Read full article here