The ideal temperature for a refrigerator is between 35 to 38 degrees Fahrenheit (1.7 to 3.3 degrees Celsius) . The temperature setting on a fridge can be a numbered dial ranging from 1 to 5, with 5 being the coldest. However, the numbers on the dial do not represent degrees, but rather refrigerant power, with the higher number indicating a colder temperature. The ideal number to set the fridge on depends on the amount of food stored and the shelf on which the food is stored. A good rule of thumb is to choose numbers three or four for a full fridge and two or three for an emptier fridge. If the temperature is set too low, it can cause ice formations that may hinder air circulation and increase energy bills. It is important to note that any adjustments to the temperature of the fridge will take 24 hours to take effect.