الساعة الحيوية BioClock app for iPhone and iPad

Simply a clock that simulates the work of your body clock, as the night begins from sunset to sunrise and the day from sunrise to sunset, with the time being accelerated or slowed down according to the length of the night or day.

Among its benefits: knowing how much of the day is left for travelers and those who practice walking, and knowing how many hours are left for those who like to sleep early, in medicine and health: exposure to the sun in order to obtain vitamin D after sunrise or before sunset by two hours, and other medical and sports uses.

Note: The clock is not expected to work in the North or South Pole or near them, as there is no clear daily sunrise and clear daily sunset.