You generally do not set a special “temperature” on the faucet itself, but you do drip it based on how cold it is outside and, ideally, run a mix of hot and cold water.
When to start dripping
Most plumbing and home safety sources suggest starting a drip when outdoor temperatures are expected to be at or below about 20°F (around -6°C) for several hours, especially overnight or during a prolonged cold snap. In homes with very exposed or poorly insulated pipes, many experts advise starting a drip anytime it will be below freezing (32°F / 0°C) for several hours.
Which water to drip
Drip both hot and cold where possible so that both hot- and cold-water lines keep moving. On a single‑handle faucet, position the handle in the middle so the drip pulls a mix of hot and cold water.
How much to drip
You only need a small, steady trickle—about one drop every few seconds up to one or two drops per second, not a full stream. Keep the drip going as long as temperatures stay at or below freezing, or until they warm up and stay above freezing consistently.
Extra pipe‑protection tips
Keep your home’s heat at or above about 55°F (13°C), even at night or when away, to help protect pipes. Also open cabinet doors under sinks and insulate exposed or exterior-wall pipes to reduce the chance of freezing.