Question: What is the ruling on a person who mistakenly breaks their fast five minutes before the Athaan (call to Prayer) of Maghrib (Sunset) Prayer is announced? The reason is related to miscalculation of time.
Answer: The time of the fast starts from the break of dawn until sunset. A person is required to make up for their fast if they mistakenly broke it before sunset. One should not solely depend on checking the time by looking at the clock when breaking the fast. The visualization of the setting of the sun must also be taken into consideration. This is because the day length differs from one day to another… read more here.