Many people who use Weather Forecast to decide if they can put out their washing for drying (or stargazing from directly above their head/zenith), also use the same logic to decide if they should go out for moon sighting or not (when it’s predicted to be visible)?

The above comparison is not correct since the distance to the horizon is usually much further away from the observation location than the horizon (where the weather forecast could be clear skies)!

The reason the actual weather may be much better at the horizon is because, cloudiness is a local phenomenon i.e. the whole region is never (or very rarely) cloudy at the same time, such that two locations, 10 – 20 miles apart may have totally different weather conditions (clear and cloudy).

The question arises, how far distance is your horizon (l) so you can estimate the weather forecast more accurately? The answer to that depends on both the height of your observation location (which is variable, h) and the radius of the earth (which is a constant, R = 3959 miles), as given in the formula below:

HorizonDiagramDistance to the horizon (l) = 1.22495 √h where h is in feet and l is in miles OR
Distance to the horizon (l) = 3.56972 √h where h is in meters and l is in kilometres (km)

1. What is the distance to the horizon for someone at 10m height of location and 1.5m tall? Distance = 1.22495 x √(32.8 + 5) = 7.53 miles OR = 3.56972 √(10 + 1.5) = 12.12 km
2. What is the distance to the horizon for someone at 1000 ft height of location and 6ft tall? Distance = 1.22495 x √(1000 + 6) = 38.84 miles OR = 3.56972 √(305 + 1.8) = 62.51 km

The above example calculations are for York (height, 10 m) and Thirsk (height, 1000 ft) in North Yorkshire.

DistanceToHorizonTable1 It is clear from the above calculations that the higher the location, the further away the horizon will be and hence the weather at that distance may not be as cloudy as the location of the observer.

Furthermore, when it’s partly cloudy, it has been found that the location near sunset may have a clear gap, allowing the moon to be easily seen, even though other parts of the skies are totally cloudy.

Therefore, never give up looking for the moon (until moon set times), even if the forecast is cloudy, since there may be a clear gap to see the moon through a break in the clouds (at the horizon)!

Note that it is advisable to use the first part of your postcode (eg. YO10) for the UK regional weather forecasts (which may include locations near your distant horizons).

Ref: How far away is the horizon? (PDF) | See also: How to Calculate the Distance to the Horizon

Related: First day's moon on UK horizon | Met Office UK weather map

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To establish the Hijri calendar with verified moon sightings by the human eye (Muhaqaq Ruyat Basari) is a communal obligation (Fard Al-Kifaya). The role of the public is to sight the moon and report it. The role of the Hilal Committee is to take the witness testimonies (Shahada) and declare the start of the lunar months (for Ibadah). Anyone who has sent a Hilal Report to the ICOUK website ( may be invited to give a testimony to ICOUK Ulama according to this policy, which may be shared confidentially (see below) with other UK Hilal Committees/Organisations (to avoid inconveniencing the witnesses with multiple testimonies).

Witness Criteria

The vast majority of the ICOUK members follow the Quran and Sunnah according to the understanding of the Hanafi Madhab (school of thought), which has the most stringent witness criteria. Accordingly, the witness must be (a) Muslim, (b) adult, (c) sane (sound mind), (d) has good eyesight, (e) reliable/good character etc.

Number of Witnesses

A minimum of two males or two females and a male witness will be required, although a greater number is most welcomed. If a female is unable to provide a testimony directly to the ICOUK Ulama, then she can still provide it through a male guardian (Mahram), known as Testimony-upon-Testimony (Shahada-Ala-Shahada)!

Remote Testimony

To help the UK Ulama/Hilal Committees make rapid and accurate Hilal decisions, we will adopt a remote testimony procedure via an audio/video conference call (e.g. Skype/Zoom). Remote testimonies will be taken individually from those who have sent (positive) ICOUK Hilal Reports and whose full identity (ID) are known to the Admins. Therefore, it is important to keep your ICOUK database profile up to date with your contact details and a recent ID Photo (of head and shoulders).

Identity Verification

An ID Photo is very helpful to establish the identity of witnesses with minimum delays. A remote testimony from a stranger (unknown person) is not acceptable. The identity of males and females will be verified separately by male and female Admins and Scholars, respectively. Once the identity has been established, a voice-only testimony (i.e. with video off) may be acceptable, InshaAllah.

Testimony Template

All witnesses will be required to use the template below, by adding the details inside the angle brackets (< >). 

I, <full name> from <city/town> testify that I saw the moon on <date/time> <before/after> sunset. The sky was <clear/cloudy> and the moon was seen on the <left/right> of sunset by <naked eye/binoculars>. The time of sunset was <hh:mm GMT/BST>.

The witnesses may be asked to provide some additional information (e.g. direction of the crescent moon horns), but the template details are the minimum required for Shariah and Scientific purposes.



Once the testimonies have been accepted by the ICOUK Ulama/UK Hilal Committees, the decision to start the month will be announced on the ICOUK website and/or social media channels. Other organisations may do the same via their own websites/social media channels. Note that the announcements for negative sighting reports are always later (than positive sighting reports), to allow the extra time for receiving all the observation results from the last sighting point/moonset time!

Confidentiality/Privacy Policy

Any testimonies provided to the ICOUK Ulama above may be shared confidentially with other UK Hilal Committees under a Non-Disclosure Agreement (NDA). All other personal details of the witnesses will be kept strictly confidential, as per ICOUK Privacy Policy and will not be disclosed to any third parties without the prior consent of the testimony provider.

Related: Importance of Moon Sighting | Importance of Reporting Hilal Sightings | Regional (Hilal) Testimony Coordinator Role (pdf)
Reference: Video Testimony Fatwa by Jamia Tur Rasheed, Pakistan (2018) [Page 10]

If you have any comments regarding the above article, please email us via our on-line Contact Us form.

Related: Importance of Moon Sighting | Why look for the moon after 29th date? [download pdf]

When Muslims go out for crescent moon (Hilal) observation, there are two possible outcomes:

  1. They actually see the moon and report the result as a positive sighting.
  2. They don't see the moon and report the result as a negative sighting.

It is Sunnah to look for the Hilal on the 29th lunar date and if there is a positive sighting then the new month begins from the next day.

However, if there are negative sightings then the new month begins from the day after the next day i.e. after completing 30-days.

Therefore, it is essential to report both positive and negative sightings to begin the new month on certainty and not in doubts.

Furthermore, negative sighting reports provide justification for completion of 30-days, hence it's important to report negative sightings (from all locations) just as positive sightings.

What if people don't report negative sightings?

The purpose of reporting Hilal sightings is to help the community (or nominated Hilal Committee) to make rapid and accurate decisions to begin the new month.

When they see the positive sighting reports on the 29th day, they can decide to begin the new month from the next day with certainty.

Similarly, when they see the negative sighting reports, they can decide to complete 30-days of the month with certainty.

venus crescentSome people only report the positive sightings and not the negative sightings. This is not helpful, because when the community (or the nominated Hilal Committee) don't see the negative sighting reports, they may fall in doubt and have to wait unnecessarily long to make a decision.

Furthermore, if lots of people report negative sightings and few people claim positive sightings, it will help them isolate mistakes easily than if no one reported negative sightings. This could happen when the moon is in the invisible phase (Mahaq) and something else is mistaken for the moon (e.g. Venus Crescent)!

"It is a misunderstanding to consider only [moon] sighting is Sunnah but sighting and reporting, both are together [as part of the Sunnah]", Mufti Yusuf Sacha (13/9/2020). [MP3 Audio]

Note that it is recommended to take photos of the horizon before and after sunset (with or without the Hilal) for supportive evidence. It could easily show the clarity of the horizons and weather conditions. However, observation reports can be submitted without photos, if they are not available!

Where should people submit the Hilal sighting reports?

Many organisations and individuals frequent the ICOUK website for reliable Hilal reports. Therefore, you should send your Hilal Sighting reports to the ICOUK website ( from the field in the first instance, which should take only about 1 - 2 mins the most (if you already have your login saved in your device). You should also SHARE it with your organisation (if any) and moon sighting groups on Social Media, as appropriate.

Checked by Shaykh Suliman Gani

Related: Importance of Moon Sighting | First day's moon on UK horizon [download pdf]

It is well-known amongst Muslim scholars and moon sighting experts that a lunar month is either 29 or 30 days long. It is never less than 29 days or more than 30 days long.

According to Islamic tradition, Muslims always look for the crescent moon (Hilal) on the 29th lunar date and if it’s not sighted then 30 days of the month is to be completed. This method works well with equatorial countries/locations where clear skies are the norm and cloudiness is an exception.

Perhaps, what is not so well-known is the fact that a lunar year has about 6 months that are 29 days long and all others are 30 days long, making a lunar year of 354 days long approximately, which is 11 days shorter than a solar year (hence Ramadan rotating through all the seasons).

The normal moon sighting practice of equatorial countries does not work in the case of the UK due to the prolonged adverse weather conditions throughout the year. These persistent adverse UK weather conditions are caused by the high and low pressures of the surrounding oceans.

Therefore, if the UK Muslims keep on completing 30-days month (as per tradition) then after about 6 months, the month length will become less than 29th days, which is not allowed in an Islamic (Hijri) Calendar system.

Similarly, if the month is prematurely ended on 29th day due to human errors (or by accepting erroneous foreign news), the future months are likely to be more than 30 days long, which is also not allowed. It is either 29 or 30 days and not less than 29 or more than 30 days.

Furthermore, the Fiqh scholars have stated that the Hilal must be seen on the 30th day (in clear sky) otherwise the start must have been wrong and if that's Ramadan then a Fast must be kept on the 31st day. In the case of the Hilal being sighted on the 28th date, a Qadha fast must be kept after Eid (see references).

Therefore, it is necessary for the UK Muslims to look for the Hilal on both 29th and the next day (30th or 1st) to minimise errors, especially in adverse weather conditions of the UK.

Besides, the above data may inform if it’s possible to rely totally on UK moon sighting reports or not in the future, without borrowing conflicting foreign news, as is the present practice.

Note that the Muslims of the Indian Subcontinent (where most UK Muslims are from), usually start Ramadan/Shawwal almost every year after sighting a 30+ hours old moon in clear sky conditions, hence it is easily seen by the naked eye.

Any sighting of a moon less than 24 hours old, especially in cloudy weather will require the help of optical aids (e.g. binoculars), which has been permitted by many UK scholars.

References (from Maulana Yakub Qasmi, 2000):

  1. Al Taqreer Ul Rafee, by Allamah Ibn Abedin Ash-Shami, Vol.2, p.146
  2. Al-Fiqh Ala Al-Madhahib Al-Arba Ah by Abd al-Rahman al-Jaziri, Vol.1 p.552
  3. Maraqi Al Falah by Allamah Tahtawi, p.359
  4. Nur al-Idah by Imam Shurunbulali, p.283

 Checked by Mufti Zakariya Akudi