One of the issues with LPG is that it freezes. Propane at a lower temperature than Butane. The container also cools as the fuel is used (the white frost round the propane bottles at Popham on a humid day indicates the LPG level).
Also of course as the temp reduces the volatility decreases. I spent 6 months living on a boat one winter and the LPG bottle would freeze up and the supply of gas for my morning shower dwindle away to nothing!
It's the inverse of the mogas problem, where it gets too volatile and gives you vapour lock
