Lemon peel thickness
Well, weird question but don't worry

I would say, scientifically, this would make perfect sense, liquid in the lemons will eventually evaporate, as they give off water to the environment they are stored in. Especially when you have your lemon storage in your refrigerator, they give off humidity to the low relative humidity in your fridge. This also happens with Oranges and generally almost all fruits. With lemons, this is especially visible in the white outer layer, as the lemon 'wants' to protect its content and its DNA (the seeds) and thus will probably give off liquid form the outer layers first (like when humans freeze in winter, it is the skin that suffers first in form of dry skin)

Long story short: I would definitely say that there is a certain correlation.

I hope this helps, Max