Weather routeing of ships has taken roughly three chronological steps. Originally, seasonal climatological weather charts, bearing little resemblance to actual conditions, gave standard routes. This somewhat passive activity was superseded by the measurement and subsequent forecasting of atmospheric and oceanographic data. Weather routeing became more complex as telex and radio facsimile routeing messages could be regularly transmitted to the ship. This form of routeing is still operational; masters can obtain radio facsimile sea and pressure charts and perform their own routeing, or employ specialist organizations which transmit the relevant routeing advice.
