Summary:

In 1997 the Interdisciplinary Centre for Mathematical and Computational Modelling (ICM), University of Warsaw launched the Internet weather service which delivers numerical weather forecasts for individual consumers and has become a basis for several weather-related scientific projects. The project "Op-erational decision-making based on atmospheric conditions" (PROZA) (started in September 2009) utilizes data obtained from weather service provided by ICM. The Research Institute of Horticulture is one of the partners in the project. The institute participates in task 3 of the project: "Application of numerical weather forecasts in forestry and fruit farming". In the frame of this task, an Internet platform for forecasting of spring frosts and fruit crop water needs was developed. https://prognozy.projekt-proza.pl/. A user (after logging in) has access to the following information (forecast is prepared for 3 days): ETo, precipitation, climatic water balance and water requirements of major fruit crops. Data on amount of (easily) available water in root zone are also available. The information provided by the service make controlling of irrigation easier and thus improve agricultural water use efficiency. The estimation of forecasting quality showed that the accuracy of forecast was high proving its practical value for fruit growers.