How long do you think oil sits on a shelf before it's put in your car???
Time doesn't change viscosity...
I don't change my oil, I take it to Valvoline to have it changed...
I started with conventional oil, changed it at 4-5k, started mod'n and went to semi synthetic and went up to 5-6k, broke into the 13's and went full synthetic.
Now I go 7-8k, never change oil by date... Always have it changed HOT.
Everyone I know, Dad, Uncle, Friends, Mechanics, etc. have told me it's best to be changed hot, and I just didn't argue.
So, to answer your question... Hot