What determines Fajr prayer time?
Fajr prayer begins at the appearance of true dawn, when the first horizontal light spreads across the horizon. This moment marks the start of the fasting day and the earliest daily prayer.
Because direct observation of dawn is not always practical, especially in cities, prayer times are calculated using astronomical methods that estimate when this condition occurs. Different calculation methods may use slightly different angles for this estimation, which can cause Fajr times to vary.