Is the air inside a refrigerator typically less humid than the air the refrigerator?

I assume your question should end with "than the air outside the refrigerator". If so then the answer is yes. Most of the humidity in the air inside the fridge (and freezer) will condense onto the cold surfaces. As new air is introduced, either by opening and closing the door, or leaving the door ajar, or thru a leaky door seal, more moisture condenses, these are some reason why a freezer will ice up quickly. Bruce