Check your setting for temp control on the inside. When it gets hot here (I know you are laughing about hot weather in Washington State) mine will go to 40 until evening and then drop to 39. Last summer while in Eastern Wa and it was almost 100 outside it struggled to stay at 42 or 43. I would open the exterior door and allow cooler air to flow through. You could also put a small fan on the outside to blow air into it. Also don't overload your refrigerator because it needs air to flow inside it. You can also buy a small refrigerator fan that will circulate the air inside (about $20 or so) to increase cooling. I've also sometimes placed a small bag of ice in a bowl and allowed it to melt.
2017 Grand Design Reflection 303 RLS
1997 GMC Sierra 3500 Dually