According to the USDA, food in your refrigerator will keep safely cold for about 4 hours during a power outage, so long as the fridge remains closed and people aren’t opening it. A full freezer will hold its temperature for approximately 48 hours, or 24 hours if it is only half full, again, so long as the door remains closed (The reason a full freezer lasts longer than a half empty one is that all the frozen food acts like ice cubes, retaining the ambient temperature. If food contains ice crystals or is 40 degrees or lower when the power comes back on, it’s safe to refreeze again.

See also ..