Freezer turns of in cold weather
Many residential refrigerator / freezers are designed to work at temperature considerably above above freezing. Most modern refrigerator / freezer have a single electric thermostat - located in the fresh food compartment. This lone thermostat will control the compressor to keep the fridge (fresh food) section at the desired temperature (usually between 34 - 38 degrees F). The freezer will get colder regardless of how cold it is already whenever the fridge thermostat turns the compressor on.
Now that you see how the thermostat works, let's look at what happens when the fridge is placed in an unheated space - like a garage. In winter time, the temperature can drop considerably below 38 degrees. If the outdoor temperature remains cold enough, for long enough - it will affect the thermostat in the fridge. The temperature inside the fridge could drop below 38 degrees, preventing the thermostat from telling the compressor to turn on. Meanwhile, the temperature in the freezer compartment slowly rises from the normal -10 to 0 F degrees. It will continue to rise until it is the same temperature as the fresh food compartment or until the thermostat in the fresh food compartment tells the compressor to turn on again. This means the freezer contents will thaw.
If the temperature in the garage is even in the 40 to 50 degree range, the loss of cold in the fridge may not happen often enough to keep the compressor coming on often enough to keep some freezer items frozen solid - such as ice cream. Remember, water freezes at 32 degrees F, other products may require lower temperatures to remain frozen, and could thaw at 28 or other temperature.