One of the cornerstones of being Muslim is fasting during the holy month of Ramadan. In the time of the Prophet Mohammed, this united Muslims in an 11 to 13 hour fast for 30 days. But with Muslims now spread around the world, the length of the day, and as such their fast, can vary greatly.

While this variation is natural, with the length of fast in Mecca itself varying by two hours when Ramadan falls in winter compared with summer, it has created entirely new theological questions as Muslims in the extreme latitudes find themselves facing nearly 24 hours a day of sunlight some years during Ramadan.

We've looked at some of the longest fasting times this year, and some of the shortest. It should be noted that how long to fast in the northern-most countries is a matter of debate. Some Muslim scholars say that fasting for the same amount of time as adherents in Mecca would suffice to fulfill the religious obligation, while others may insist on a strict sunrise-sunset fast.

Here are the countries where Muslims are fasting the longest versus those fasting the shortest based on fajr and maghrib timings on Islamic Finder .

Longest fasting hours

Fasting can last as long as 21 hours.

Iceland

Fasting can last as long as 21 hours in Iceland.

Sweden

In certain cities in Sweden including Uppsala and Stockholm, Muslims fast for more than 20 hours a day.

Norway

Just a bit over 20 hours

Greenland

Just over 20 hours

Finland

Just over 20 hours

Denmark

Around 19 hours

Russia

A bit over 19 hours in cities such as Moscow.

Shortest fasting hours

Fasting, on average, lasts about 11 hours in the countries below - about two and a half hours shorter than in Mecca this year and nearly 10 hours shorter than in Scandinavia.

New Zealand

Argentina

South Africa

Chile

Australia