Depending on your model there is usually some method to adjust the temperature. If there is no knob, setting etc. then there will most likely be a temp sensor inside the fridge near the side towards the back attached to the vanes. It can be slid up or down to make the fridge warmer or colder.
I am in AZ and when temps are over 100 its difficult to get the fridge below 45. After sundown it will cool to normal 35-38.
If the fridge is filled with solid food items it stays cool through the day. If filled with liquids (beer, soda, milk etc) it will do considerably better.
