Morning

Morning is the period of the day beginning at dawn (the first light appearing in the east before sunrise) until noon. It is the time when the sun rises in the sky and temperature increases gradually.

The exact boundary of morning varies by custom and convention. In formal timekeeping, morning typically runs from midnight (12:00) to noon (12:00), the basis of the 'AM' and 'PM' designations in the twelve-hour clock system. In common usage, morning begins when people wake or when the sun rises.

Scientific explanation

Morning arises from the rotation of the earth on its axis. The part of Earth facing the sun receives light. Twilight brings light scattered through the atmosphere to areas where the sun has not yet risen, causing light to precede sunrise.

The time of sunrise depends on latitude and season. In regions near the equator, such as Somalia, the variation in sunrise time throughout the year is small. At higher latitudes, the difference is much greater: in summer, sunrise comes much earlier, while in winter it is delayed.

Human physiology and circadian timing

The human body has a circadian rhythm regulated by light. In early morning, cortisol hormone levels rise while melatonin falls, which is linked to alertness and waking. Natural morning light is used to regulate sleep schedules.

Custom and usage

Morning is widely recognized as the time when work, education, and breakfast begin. Some religions have prayers timed to morning light; in Islam, the dawn prayer is performed between true dawn and sunrise. The greeting 'good morning' is a universal convention for this time.