The Quin app summarises your past blood sugar readings to show you how your blood sugar has previously reacted around the same time of day.
As you start to record blood sugar in the app or in Apple Health, the app will summarise all previous blood sugar readings from the last 30 days around the time you are viewing the app and for the next 5 hours. This may give you an indication of how consistent your blood sugar tends to be over time.
In future releases, recording actions like food, insulin, correction doses, hypo treatments and activity will also affect the graph. This will further give you an indication of how your blood sugar usually reacts to each of these actions.