At what temperature does propane become a liquid?

Propane becomes a liquid at -44°F (-42°C) under standard atmospheric pressure. This temperature is known as the boiling point of propane. Above this temperature, propane exists as a gas, while below it, propane can condense into a liquid. Understanding this point is crucial for handling propane safely, especially in the context of storage and transportation, where it is often kept in its liquid form under pressure to facilitate easy transport and use.

The other temperatures listed do not reflect the conditions at which propane transitions from a gas to a liquid. Specifically, 0°F and -32°F are both higher than the boiling point of propane, meaning it would be in gaseous form at those temperatures. The freezing point of water at 32°F also surpasses the liquefaction point for propane, further emphasizing why -44°F is the correct reference for its liquid state under regular atmospheric circumstances.