The ideal temperature for a refrigerator is between 35 and 38 degrees Fahrenheit, according to the U.S. Food and Drug Administration (FDA) . However, the temperature controls on many fridges only allow you to choose from a series of numbers, usually 1 through 5, with 1 being the coldest and 5 being the warmest. On every fridge, the rules for the coldest settings are always the same: the higher the number goes, the colder the fridge will maintain. Setting it to 5 will make your fridge the coldest. If youre always storing plenty of food, you need the colder settings (3 to 4). If youre not storing as much, choose between 2 and 3. If the temperature is very low, ice will form, and it may prevent air circulation. Ice could also cause the fridges inner thermostat to malfunction, leading to electronics failure. If ice accumulates, knock it off, lower the temperature, and bear in mind that the change will take place in at least 8 hours.