Regulation 5 - Meteorological Services and Warnings


  • Contracting Governments are obliged to provide and promulgate meteorological information and warnings to shipping.
  • Provisions for recording and reporting observations from ships (5.2)
  • Transmission of ship reports (5.3)
Regulation 5
1. Contracting Governments undertake to encourage the collection of meteorological data by ships at sea and to arrange for their examination, dissemination and exchange in the manner most suitable for the purpose of aiding navigation.* Administrations shall encourage the use of meteorological instruments of a high degree of accuracy, and shall facilitate the checking of such instruments upon request. Arrangements may be made by appropriate national meteorological services for this checking to be undertaken, free of charge to the ship.

In particular, Contracting Governments undertake to carry out, in co-operation, the following meteorological arrangements:

2.1 to warn ships of gales, storms and tropical cyclones by the issue of information in text and, as far as practicable graphic form, using the appropriate shore-based facilities for terrestrial and space radiocommunications services.
2.2 to issue, at least twice daily, by terrestrial and space radiocommunication services**, as appropriate, weather information suitable for shipping containing data, analyses, warnings and forecasts of weather, waves and ice. Such information shall be transmitted in text and, as far as practicable, graphic form including meteorological analysis and prognosis charts transmitted by facsimile or in digital form for reconstitution on board the ship's data processing system.
2.3 to prepare and issue such publications as may be necessary for the efficient conduct of meteorological work at sea and to arrange, if practicable, for the publication and making available of daily weather charts for the information of departing ships.
2.4 to arrange for a selection of ships to be equipped with tested marine meteorological instruments (such as a barometer, a barograph, a psychrometer, and suitable apparatus for measuring sea temperature) for use in this service, and to take, record and transmit meteorological observations at the main standard times for surface synoptic observations (i.e. at least four times daily, whenever circumstances permit) and to encourage other ships to take, record and transmit observations in a modified form, particularly when in areas where shipping is sparse.
2.5 to encourage companies to involve as many of their ships as practicable in the making and recording of weather observations; these observations to be transmitted using the ship's terrestrial or space radiocommunications facilities for the benefit of the various national meteorological services.
2.6 the transmission of these weather observations is free of charge to the ships concerned.
2.7 when in the vicinity of a tropical cyclone, or of a suspected tropical cyclone, ships should be encouraged to take and transmit their observations at more frequent intervals whenever practicable, bearing in mind navigational preoccupations of ships' officers during storm conditions.
2.8 to arrange for the reception and transmission of weather messages from and to ships, using the appropriate shore-based facilities for terrestrial and space radiocommunications services.
2.9 to encourage masters to inform ships in the vicinity and also shore stations whenever they experience a wind speed of 50 knots or more (force 10 on the Beaufort scale).
2.10 to endeavour to obtain a uniform procedure in regard to the international meteorological services already specified, and as far as practicable, to conform to the technical regulations and recommendations made by the World Meteorological Organization, to which Contracting Governments may refer, for study and advice, any meteorological question which may arise in carrying out the present Convention.


3. The information provided for in this regulation shall be furnished in a form for transmission and be transmitted in the order of priority prescribed by the Radio Regulations. During transmission "to all stations" of meteorological information, forecasts and warnings, all ship stations must conform to the provisions of the Radio Regulations.
4. Forecasts, warnings, synoptic and other meteorological data intended for ships shall be issued and disseminated by the national meteorological service in the best position to serve various coastal and high seas areas, in accordance with mutual arrangements made by Contracting Governments, in particular as defined by the World Meteorological Organization's System for the Preparation and Dissemination of Meteorological Forecasts and Warnings for the High Seas under the Global Maritime Distress and Safety System (GMDSS).

* Refer to the Recommendation on weather routeing adopted by the Organization by resolution A.528(13).

** Refer to regulations IV/7.1.4 and IV/7/1.5.

MCA Guidance
1. Regulation 5 emphasises to Administrations, Companies and Masters that although there have been significant technological developments in weather forecasting, weather reports from ships still play an essential role in providing accurate weather forecasts.
2. The Regulation obliges Administrations to encourage the use of highly accurate instruments and proposes that national meteorological services check the instruments' accuracy free of charge; (paragraph 1) this service is provided by the Met Office for UK Ships. Paragraph 2.6 states that weather reports shall be transmitted free of charge.
3. The Met Office, the UK national meteorological service, provides shipping forecasts for north European sea areas and UK inshore waters, which are promulgated throughout the day on radio, NAVTEX, SafetyNET and Internet. Severe weather warnings are broadcast as soon as possible. Navigational Warnings are promulgated by the UKHO.
4. The MCA administers the budget for these services under a Memorandum of Understanding with the Met Office.
5. The second footnote refers to SOLAS Chapter IV, Regulations 7.1.4 and 7.1.5, which lay down the requirements for ships' radio equipment for receiving NAVTEX and other safety information.

IMO member Governments are urged to support the World Meteorological Organizations's (WMO) Voluntary Observing Ship Programme (VOS). The MCA strongly encourages UK companies to volunteer their vessels. Despite technological developments, ship meteorological reports still play an essential role in providing accurate forecasts and will continue to do so for the foreseeable future. UK shipowners should contact the Meteorological Office to nominate their ships for the Voluntary Observing fleet.

MSC/Circ.1017 - Participation in the WMO Voluntary Observing Ships' Scheme underlines the importance of the Scheme. This circular is reproduced at ANNEX 4,

Full details of the Scheme can be found on the WMO Website on the following link: WMO Voluntary Observing Ship Scheme (

MSC/Circ.1017 (also at ANNEX 4)

MGN23 - Use of NAVTEX


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