The Weather Risk app provides user-friendly, agricultural-focused weather and water availability indices designed to support short-term agricultural planning and decision-making, typically on daily to weekly timescales. It serves a wide range of agricultural stakeholders, including, among others, farmers, agricultural extension and field officers, farmer organizations, planners and technicians, cooperatives, seed and agrochemical companies, agricultural insurance providers, local government, policymakers, and researchers.
All weather-related indices in the app (i.e., all tabs except for the water indices tab) are based on gridded observational weather station data from the Agricultural Research Council (ARC). These datasets are updated in near-real time, typically with up to two days of delay. Several weather indices also include forecast information derived from the Weather Research and Forecasting (WRF) model. When the daily WRF forecast runs successfully, the forecast layers displayed at the end of each day correspond to the same day updated outputs.
Within the water indices tab, only the Monthly Surface Water Anomaly Index updates regularly (on a monthly schedule). Other water-related products are static, representing long-term average or baseline conditions.
Users who require detailed information on how to interpret the indices, data sources, update frequencies, and processing steps can consult the User Guide. More technical information, such as the datasets used to calculate each index, is available in the User Guide section: Input data used to calculate the indices.
The Weather Risk app was developed by the Agricultural Research Council (ARC) as part of a project funded by the Water Research Commission (WRC) (Project No. C2023/2024-01182).
The Weather Risk app was developed by the Agricultural Research Council (ARC) with funding from the Water Research Commission (WRC). A full list of contributors involved in developing the app is provided in the acknowledgements section of the user guide.
Above this, we gratefully acknowledge the use of data from a range of national and international sources, including the ARC’s own datasets, GeoTerraImage and EkoSource, the South African National Space Agency (SANSA), the Department of Water and Sanitation (DWS), the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Crop Estimates Consortium of the Department of Agriculture. Specific data providers are acknowledged in the app’s user guide under the section input data used to calculate the indices.
Related Platforms
If you are looking for complementary tools and data, the following platforms may be of interest:
• ARC Weather App – A subscription-based platform offering access to the Agricultural Research Council’s (ARC) weather station data, which form part of the datasets used in developing this site.
• The Umlindi Newsletter – A monthly agricultural climate watch providing insights into current conditions. Users can subscribe to receive the newsletter directly.
The information and data provided through the Weather Risk site are intended for general guidance and decision support in agricultural planning. While every effort has been made to ensure accuracy and relevance, several important limitations should be noted.
Weather station coverage across South Africa is uneven, and the observations used in this platform are spatially interpolated to create continuous national surfaces. Users should therefore be aware that conditions at specific locations may differ from the mapped estimates. The spatial distribution of operational weather stations from the Agricultural Research Council (ARC) is included as an optional map layer (accessible via the top-right panel) to support interpretation.
Forecast information presented in the app is derived from a single numerical weather prediction system, the Weather Research and Forecasting (WRF) model. Validation of the WRF-based forecast products is ongoing, and forecast skill may vary across regions, seasons, and variables. Users are advised to interpret forecasts cautiously.
All datasets included in the platform, including observational, remotely sensed, and forecast products, are documented in detail in the user guide's input data to calculate the indices section, while the section on known limitations details limitations of the datasets. This user guide also outlines the processing methods, update frequencies, and key considerations relevant to interpreting each dataset and index.
Given its recent release, the Weather Risk site is currently in a testing and refinement phase as we continue to assess its suitability for fully operational decision-making. Although the indices and datasets have been carefully developed, they are still being evaluated for robustness, consistency, and performance across different regions and seasons. As a result, users should regard the outputs as advisory tools intended to support situational awareness and planning, rather than as definitive or authoritative guidance. Operational decisions should always be informed by multiple information sources and professional judgement.
The Agricultural Research Council (ARC) and the Water Research Commission (WRC) do not accept liability for any loss, damage, or decisions made based on the outputs presented. Users should interpret all indices in conjunction with local expertise, contextual knowledge, and other complementary information sources. Use of the app constitutes acceptance of this disclaimer.
