Methane becomes a liquid at atmospheric pressure at approximately −162 °C.
Natural gas is mainly methane, and cooling it to about −162 °C turns it into liquefied natural gas, or LNG, at near-atmospheric pressure. Liquefaction reduces the gas's volume to roughly one six-hundredth of its gaseous volume, making long-distance transport by specialized ship practical where pipelines are unavailable.
LNG is not a different chemical fuel from natural gas. It is natural gas in a cryogenic liquid state. At the destination, regasification warms the LNG and returns it to a gas that can enter pipelines or be used by customers.
The temperature is often rounded in public explanations, and the precise boiling point depends on pressure and composition. LNG also requires insulated tanks, controlled handling, and equipment designed for extreme cold. It should not be confused with liquefied petroleum gas, which consists mainly of propane and butane and liquefies at much warmer temperatures.