This is what we found on Wikipedia regarding the Layali Obhur in Jeddah:

Ramadan is the ninth month of the Islamic calendar. It is observed by Muslims worldwide as a month of fasting (sawm), communal prayer (salah), reflection, study of the Quran, charity, and strengthening community ties. It is also the month in which the Quran is believed to have been revealed to the Islamic prophet Muhammad, known as Laylat al-Qadr. The annual observance of Ramadan is regarded as one of the five pillars of Islam and lasts 29 to 30 days, from one sighting of the crescent moon to the next.

Fasting from dawn to sunset is obligatory (fard) for all Muslims who have reached puberty, and who are not acutely or chronically ill, traveling, elderly, breastfeeding, pregnant, or menstruating. The predawn meal is suhur, and the nightly feast that breaks the fast is iftar. Although rulings (fatawa) have been issued that Muslims who live in regions with a midnight sun or polar night should follow the timetable of Mecca, it is common practice to follow the timetable of the closest country in which night can be distinguished from day.

The spiritual rewards (thawab) of fasting are believed to be multiplied during Ramadan. Accordingly, during the hours of fasting, Muslims refrain not only from food and drink, but also from all behavior deemed to be sinful in Islam.