So I have both my GPU and CPU marked, but my GPU dosent run at all when the CPU is marked, but dose when it isnt

I am new to Mining, only have been doing it for the past couple of months. I wanted to know if I could make a special box that my mining rig would stay in and leave it outside. This box would be sealed, so water cant enter, and would have filters on it for dust and stuff. What I want to know is if condensation will occur? I know that it occurs when warm air touches something colder, if im correct. So would condensation still occur if I put my mining rig outside when its around -9.4 C (15 F), when my PC temps are around 65 C (149 F)?

So I just do mining for fun! I dont intend to live off this nor make much money from it as well. Right now I have a spare PC with a AMD 6-Core CPU and a AMD R7 250... I get around 0.67 USD a day.... This isnt much and im ok with that! Most of the money I get is from the CPU, not the GPU. So if I was to buy a GTX 1050 TI for around $170.... How much will this go up. In HASH. I use NiceHashMiner for Bitcoin