I get a lot of questions about whether it is safe to operate a refrigerator or a freezer in a non-air conditioned environment, such as a garage or porch. Most manufacturers stipulate otherwise in most cases. Here is the reason why it is unwise to do this:
Refrigerators have a mineral oil bath for the compressor. In fact this oil is permeated throughout the system in the refrigerant as well. If the fridge is in an environment where the ambient temperature drops below 58 oF. this oil can develop viscosity issues, causing it to congeal and permanently block the sealed system. It can also damage the reed valves in the compressor under these conditions.
The only units which are rated for outdoor or extreme cold usage have what is called a crankcase heater in the compressor circuit. Many air conditioners use this same technology to allow heat pumps to work in frozen conditions. Domestic refrigerators as a rule do not have this system, and must be kept in the same environment that you live in unless your User Guide says otherwise. Additionally, those units which are placed in a hot environment, such as a commercial kitchen, are subject to very long run times and frequent compressor damage associated with overheating. The ideal ambient temperature range for most refrigerators is 70-82o