Abstract: Forecasting systems are basic tools for integrated and biological plant protection. ‘VitiMeteo’ (VM) is an extensive forecasting system for viticulture. It is a cooperative project between the State Institute for Viticulture and Oenology, Freiburg (Germany), the Swiss Research Station Agroscope Changins-Wädenswil (Switzerland), and the company GEOsens, Ebringen (Germany). Basically, the system consists of data sources, a database, expert software and the presentation of data on the internet. The data flow is organized as follows: (i) weather data is stored in a database; (ii) transfer of weather data to the expert models, (iii) publication of main results on the internet using graphs and tables. Core of this system is the database ‘Agrometeo’, where all data from different weather stations and related forecast data are stored.Over the years VitiMeteo grew step by step. ‘VM Plasmopara’ was the first module, created in 2002; it calculates the most important steps of the infection cycle of downy mildew. Next component was the growth model ‘VM Meteo Growth’, which was programmed in cooperation with H.-R. Schultz (HS Geisenheim). The software ‘VM Oidiag’, based on work of W. Kast (LVWO Weinsberg), is a powdery mildew risk model. Other expert models are ‘VM Insects’ and ‘VM Hyalesthes’. Practical applications are the calculations of the flight start of the grape berry moth and of Hyalesthes obsoletus. ‘VM Hyalesthes’ is built on the works of M. Maixner (JKI Siebeldingen). The latest software is ‘VM Black rot’, which models the important parts of the life cycle of Black rot. The software was developed together with D. Molitor (CPR Belvaux), due to his recent work. ‘VM Data Graph’ is an additional, valuable computer program for the visualization and validation of weather data. Linking weather forecast with all models, provided from the company Meteoblue (Basel), marked a milestone in the development of the system. All expert software permits the variation of important model parameters. This parameterization has proved to be a main advantage in the development of the models. It allows the optimization of the models continually. In contrast to other forecasting systems, research institutions own the complete software. Therefore current research improvements will be integrated quickly. The ‘VitiMeteo system’ is open, flexible and innovative, because research results and new models can be transferred into practice more quickly than before.