We stored methanol drums outside here in western Pennsylvania for years. So they were sometimes bitter cold and then extremely hot. We used the methanol as a solvent pumping it through our pilot plants to clean and absorb water. The 2 biggest problems with long term storage is not having the bung tight and using non-lined metal drums. Eventually the drums will deteriorate and contaminate the methanol. Plastic drums or drums lined with a phenolic resin are the best storage containers. You can tell if a drum has the phenolic resin liner by looking into the drum. If the walls seem to have brown color, that's the resin coating.