It is easy to underestimate the seemingly humble calendar. Rather than a list of days and months to be pinned to the wall or stuck on the fridge, the calendar one follows has a profound influence not only on daily life, but one's concept of time itself.
For a reminder of this, one need only read the 231 pages of Al Taqweem Al Hijri, an Islamic calendar recently released in its 13th edition that is far more than a list of days and months. It is a wealth of information on everything from upcoming astronomical phenomena, prayer times, weather forecasts and even advice on which crops to grow and when.
Produced by a team of scientists and heritage experts, it is based on verses from the Quran, complicated astronomical formulas, meridians of the celestial sphere, traditional Bedouin knowledge and the navigational expertise of seamen.
The calendar stands at the intersection of science, religion and heritage. And while some might wonder how reliable its predictions are, they ring the truest to those who have lived here the longest.
"We can never say the calendar is 100 per cent accurate, but it is as close as we can get to what it will most likely be at that period of time," said Dr Hamid Al Naimiy, referring to Al Taqweem Al Hijri's weather forecasts.
Dr Al Naimiy is one of the calendar's authors. He is also vice chancellor for academic affairs at the University of Sharjah, a professor of astronomy and astrophysics, and president of the Arab Union for Astronomy and Space Sciences.
"Astronomy affects your everyday life more than you know," he says.
With more than 40 years of experience, the Iraqi scientist is not only a member of Nasa, he is a celebrity for his television debates with Islamic scholars over the scientific interpretation of Quranic verses.
"The Quran complements our scientific discoveries. It mentions things like the big bang theory, virtual position of the stars, eclipses and even makes reference to how the celestial bodies are in motion and 'swim' along, each in its rounded course," he said.
The calendar, published by the Emirates Heritage Club, quotes one Quranic verse in particular: "They ask you concerning the New Moons. Say: they are but signs to mark fixed periods of time in the [affairs of] people, and for pilgrimage." (2:189)
To predict when important religious dates will occur, Dr Al Naimiy's employed the widely used scientific "new moon" formula and adjusted it to take into account the time needed for the crescent to become visible.
The calendar predicts that this year, the first day of Ramadan will be July 21 and the three days of Eid Al Fitr will be August 19 to 21.
Eid is predicted to be extremely hot with high humidity and strong northerly winds.
Unstable northern west winds called Al Sarayat are forecast for April, with the first days of the Taurus zodiac phase (starting around April 20) bringing the last major storm before the hot weather settles in during May.
As for crop forecasts, the date palms will be abundantly fruitful and this month is the best time for planting mint, beans and aubergine, and April is best for planting palm trees and corn.
"There are talks of using science for the sighting of the crescent to mark Eid in order to make it more unified across the Muslim world," he said, referring to a conference of scientists and scholars earlier this year in Mecca.
The traditional method is to go out and look.
The calendar incorporates traditional calculations, thanks to the research of the Emirati civil engineer Sakher Saif.
"The science and factual parts were covered well, so I came in to add the historical and heritage part to the calender," Mr Saif said.
Bedouins in the desert use different stars and calculations than the settlements in the mountains and along the coast, but all depend on a four-season calendar known as Al Drour that was drawn up according to the stars.
"People feel traditional navigational tools are complicated, but they are not. They relied on what was in the environment and nature, and so it is easy to reference and build on," Mr Saif said.
One of the most important stars, Suhail, also known as Canopus, inspired the use of the Suhail calendar in the Gulf for centuries.
The Suhail calendar is based on 10-day units divided into 36 sections that begin with the star's rising on a late summer dawn. It appears in the sky in mid-August every year and remains visible until late winter in the Arabian peninsula. Its appearance promises the end of the hot season and the beginning of a more moderate climate.