Thanks. Seems obvious once it's explained!A quick search turned up this. Not sure how accurate it is across all boilers. It mentioned it doesn't heat the glycol as much in warmer weather compared to when it is really cold out. Also mentions the 65F cutoff where it goes into sleep mode which I remember the heating guy mentioning. They mainly talk about radiator heating but this could apply to in floor heat. The temps are different though. For instance the floors get 120F for a target temp. Where when I get the lines up and running out to a water to air heat exchanger, they will be at 160F.
Outside Air Reset For Boilers