I ask because I just switched them on for a couple of schedules, so there was no adjustment yet and I wanted to “catch” them up to high summer time. I looked at other schedules that had the adjustment on and found the value ranged all over the place. I even have two schedules (fixed) for the same zones since I want to run one day in the evening and the other day in the early morning. (They are on watering day restrictions.) One schedule had an adjustment of 44%, the other was at 27%.
Ideally I would like to set the watering times to what they “should” be on a “neutral” day–that is one where the adjustment is 0%. Maybe a Spring day. Then I would expect the adjustment to go up in the summer and down in the winter.