Due to a misinterpretation of the ORS, wrong decisions of planting time lead to crop failure and high economic losses within the Volta basin. In addition, farmers reported an increasing variability of the ORS, especially since the 1980s.
The meteorology and climate research group of the GVP has developed a scientifically based prediction scheme for the determination of the Onset of the Rainy Season.
The ORS can be predicted spatially for different regions of the Volta basin, which helps the farmers to determine the right time-frame for sowing.
Maps of mean ORS dates (Figure) and their standard deviations have been developed to support agricultural extension workers and farmers in their determination of the correct sowing time. ORS maps can now be produced routinely every year.