Liquids become gases when their kinetic energy overcomes the intermolecular forces between molecules. As the temperature rises, the kinetic energy increases and the liquid eventually reaches it's boiling point. read more
Methane, being a very small and very NON linear molecule has very little London forces. Since methane has low intermolecular forces of attraction and since the boiling point and intermolecular forces of attraction are directly proporational, therefore methane has a low boiling point. read more