To adjust the temperature of your bottom freezer refrigerator, you'll first need to figure out if your unit has electric or manual controls. If it has electric controls, you can adjust the temperature using a digital pad on the exterior or within the unit's interior. If it has manual controls, you can gently turn a dial to your desired temperature. (If the dial uses numbered tick marks, "1" is usually considered the warmest.) To safely store food, set the refrigerator temperature to 35 F and the freezer to zero degrees.