If the weather outside goes below minus 44 degrees Fahrenheit, then the propane won’t turn into a gas, as that is the boiling point of propane. When the gas enters the house, the pipes will be warmer inside, so the gas will warm up. If the propane tank is in the ground then the year-round ground temperature below the frost line may be 55F, so the propane will be warm and there will be adequate gas pressure. If the tanks are sitting outside in the cold, then it might be a good idea to warm them to at least zero degrees F so there will be enough pressure to use the gas. Insulation is not required.
Kenny black pipe exposed to the elements it is always a FANTASTIC idea to protect them with either 2 coats of red lead paint then a finish coat Or wrap them with plastic to protect them from rusting out.