telegraphic codes and message practice, 1870-1945
telegraphy in meteorology


It was evidently possible to study with advantage, the progress of atmospheric changes only when the telegraph lines had become widely extended over the earth's surface.

Cleveland Abbe, "Historical Notes on the Systems of Weather Telegraphy, and especially their Development in the United States." American Journal of Science and Arts, 3rd. ser. 2 (1871) 81-88

Meteorology developed in the nineteenth century on the back of telegraph and cable networks, by which widely scattered stations could submit their observations to a central point. Those "synoptic weather observations" were — and are today — made periodically, e.g., 8:00 am and 8:00 pm, and cover data on sky cover, state of the sky, cloud height and description, maximum and minimum temperatures, wind speed and direction, special conditions, &c. It is hard to imagine meteorology and weather prediction in the absence of the intelligence exchanged over telegraph networks.

Aeronautics was a second factor that pushed meteorology in new directions — mainly up; in so doing, aeronautics also vastly increased the need for observational data. Conventional land-based observations and their telegraphed transmissions weren't up to the new requirements; telegraphy, it was charged, imposed restrictions on the number of observations that could be transmitted, so complex and expensive was a telegraphed message (Friedman 1989: 146-49). This might be debated : witness the density of data that could be packed into a single word or 11-figure cipher by use of a cotton or chain and sectional cipher code, for example. But telegraphy was not static, and continued to evolve and even morph into different forms. Examples include the gradual transition to numeric codes in the 1930s, and the logical move toward telemetry from radiosondes.

Coded telegraphic messages involved structuring of data, if only by virtue of the structure provided by the codebook's tables and sequences. Meteorological codes represent the summa of that structuring : sequential assembly of formulaic message components, in a rule-bound process that would evolve through teletype symbol weather reports and on to telemetric rulesets like the National Weather Service's Standard Hydrometeorological Exchange Format.

Gathered on this and linked pages are transcriptions of historical material on the role of telegraphy in meteorology, extended descriptions of some weather and related codes, and some annotated links to material available elsewhere. These are arranged chronologically below.

  1. weather reports, storm signal system
    W. J. Johnston in his Telegraphic Tales and Telegraphic History (New York 1880) provides an account of telegraphic practice in the weather service.
    See transcription here.
    The code used naturally predated the 1880 publication of this popular book.
  1. United States Signal Office
    Ralph Abercromby (1842-1897) concluded one of his meteorological travels with an inspection of the United States Signal Office in Washington, D.C. A detailed description of the workings there can be found in his Seas and skies in many latitudes; or, Wanderings in search of weather (London 1888) : 413-21.
    His account of the indications room — see transcription here — details how telegraphic reports are processed for the creation of weather maps and predictions.

    Information on Abercromby is not hard to find; he makes an important appearance in Richard Hamblyn's The Invention of Clouds : How an amateur meteorologist forged the language of the skies (New York 2001). The amateur that is the subject of Hamblyn's excellent book is not Abercromby but Luke Howard (1772-1864).

  1. Weather Code — 1896
    U. S. Department of Agriculture, Weather Bureau.
    Weather Code, December 1, 1896
    Description and extracts here
  1. How a weather map is made
    "How a weather map is made." Scientific American 82:3 (Jan 20, 1900): 38
    transcription here
  1. Weather Code (Numeral System) — 1939
    U. S. Department of Agriculture, Weather Bureau.
    Weather Code (Numeral System) 1939
    Description and extracts here

It might be said that meteorological telegraphy would come to abandon human users at the level of coding and decoding, as sensor devices and processing itself became automated. SHEF is a "documented set of rules for coding of data in a form for both visual and computer recognition... designed for interagency sharing of data, visual and machine readability." It takes data fed from automated sensors — data sequence identified in a header line — and "fully qualifies the data so that receiving databases have all the necessary information to describe the data."

  1. Standard Hydrometeorological Exchange Format (SHEF) Manual
    National Weather Service Manual 10-944.
    Available via
    or directly (18 feb 06) at
  1. Australia
    Federation and Meteorology : The Case of Meteorology, 1876-1908
    This link leads to a passage on the realization of the importance of telegraphy to meteorology over large areas beyond particular localities.
    Home, R. W. and Livingston, K. T. "Science and Technology in the Story of Australian Federation: The Case of Meteorology, 1876-1908", Historical Records of Australian Science 10:2 (December 1994): 109-27.
    This is one of several articles collected together in Federation and Meterology project of the Australian Bureau of Meteorology. There is a reference to the American word-based code, which is preferred over the British Numerical Code, at page 26.

Telegraphy is woven into the literature of and on meteorology, including —

  1. T. B. Maury. "The Telegraph and the Storm : The United States Signal Service." Harper's New Monthly Magazine 43:255 (August 1871) : 398-418 (here)
  2. Friedman, Robert Marc. Appropriating the Weather : Vilhelm Bjerknes and the Construction of a Modern Meteorology (1989): 146-49, for a discussion of the post World War 1 setting in a section entitled "Weather and Forecasting Redefined."
  3. James Rodger Fleming. Meteorology in America, 1800-1870 (1990)
  4. Katharine Anderson. Predicting the Weather : Victorians and the Science of Meteorology (2005)

26 feb 06