The temperature in a refrigerator is preset at the factory. The normal is 37 degrees Fahrenheit. You can, of course, adjust the temperature using the controls to make it higher or lower for your cooling needs. The exact inside temperature of your refrigerator will depend on the temperature of the room. According to Whirlpool, the refrigerator temperature will be 6 degrees higher or lower than the set point due to the ambient temperature. Other factors affect the coldness as well.
Position the refrigerator so it's located away from all heat sources. Don't place it near a cook stove, wood stove, warm air register or windows where direct sunlight streams in.
Leave an air space between the refrigerator and the wall. This will allow air to circulate around the condenser coils so they can work properly. Vacuum the coils on a regular basis to keep them clean.
Inspect the door seals on the refrigerator from time to time. Leaky seals let the cold air out and the warm air in. Open the door and place a dollar bill on the seals. Close the refrigerator door. Try to pull the bill out. If it slides out, you need to replace the seals.
Store only cool or cold foods in the refrigerator to make it colder, recommends the Consumer Energy Center. Avoid placing hot foods in it. Let them cool down first.
Keep the refrigerator fairly full to keep it colder, but don't overfill it. The cold items will help retain the coldness better than empty space. Place containers filled with cold water inside the refrigerator if you don't store much food. Leave spaces for the air to circulate.