Ramadan lasts 29 or 30 days, yet the number of hours people fast can differ by many hours depending on where they live and when Ramadan falls. Two things drive this: the Islamic calendar is lunar, so Ramadan moves through the seasons, and the length of daylight depends on latitude. Here is how both work.

Why Ramadan Moves

The Islamic calendar has 12 lunar months of 29 or 30 days, a total of about 354 days. A solar year is about 365 days. Ramadan therefore arrives roughly 10 to 11 days earlier on the solar calendar each year. It takes about 33 years to cycle through all the seasons.

This means that in some years Ramadan falls in the short days of winter, and in others in the long days of summer. A generation of Muslims in the same city may experience fasts of very different lengths over their lives.

How Latitude Changes the Fast

The fast runs from the start of dawn (Fajr) until sunset (Maghrib). Near the equator, day length is nearly constant, about 12 to 13 hours of fasting all year. Further from the equator, the difference between summer and winter grows. As a rough guide:

  • At mid-latitudes, such as the Mediterranean or much of the southern United States, a winter Ramadan can mean fasts of around 11 to 12 hours, while a summer Ramadan means around 15 to 16 hours.
  • At higher latitudes, such as northern Europe, a summer Ramadan can bring fasts of 17 to 19 hours or more, and a winter one 9 to 10 hours.

These figures are approximate and change from day to day, and by exact location. Use a prayer times tool for your own city. Our guide to how prayer times are calculated explains the methods behind Fajr and Isha.

Why Fajr Times Can Differ

Fajr is based on the angle of the sun below the horizon at dawn, and different organisations use different angles, for example 15 to 18 degrees. A larger angle means an earlier Fajr and a longer fast, by several minutes. Many communities follow the method their local mosque or scholars have adopted, so check which one is used where you live.

Extreme Latitudes

In some locations, especially far northern ones in summer, twilight may never fully end, so the usual signs for Fajr and Isha may not appear at all for weeks. Scholars and fiqh councils have suggested several approaches, including:

  • Following the timings of the nearest city where the signs are clear.
  • Using the timings of a fixed latitude, such as the nearest day with normal signs.
  • Dividing the night into fractions (for example, one-seventh or one-half of the night) to define the start of the fast.
  • Following the timings of Makkah.

Opinions differ, and communities often follow guidance from local scholars. If this affects you, ask a qualified scholar or your local Islamic council.

Health and Practical Tips for Long Fasts

  • Eat a balanced pre-dawn meal with slow-release foods, such as oats, eggs, yoghurt and fruit, and drink water steadily.
  • Break the fast with water and dates, and then eat a regular meal rather than overeating.
  • Limit very salty or sugary foods that increase thirst.
  • Sleep in blocks when possible. Fasting in long summer days often shortens sleep.
  • If you have a medical condition, take medicine, or are pregnant or breastfeeding, talk to your doctor and a scholar, because exemptions exist in Islamic law.

Our guide to daily water intake also covers hydration planning when you cannot drink during the day.

Dates and Moon Sighting

The start of Ramadan depends on the new moon. Some communities follow a local moon sighting, others follow calculations, and some follow the announcement of a particular country. Because of this, the start date can differ by a day between places. Use a calendar tool for an estimate, then confirm with your local authority.

Your Next Step

Check the expected Fajr and Maghrib times for your city and calculate the length of your fast. Our Ramadan calculator helps you plan, and you should confirm the start date with your local moon-sighting authority. This is general information, not a fatwa.