Although Botswana is generally arid to semi-arid, heavy rainfall events do occur which at times cause floods. Several weather systems influence the country’s rainfall; hence, it is crucial to improve understanding of these systems to improve forecasting of the country’s weather and climate. The study analyses the selected case of the storm that occurred in Mahalapye and the surrounding areas, Botswana, on 9 December 2018 (Mahalapye storm for short) whose impacts include flooding of some roads and submerged homesteads. The storm is analysed to improve its understanding including identification of the weather systems that triggered it. Observed and modelled mean sea level pressure, 500-mb geopotential heights and rainfall data are used in the analysis. Observed rainfall data used are gauged data. The study also updates the country’s rainfall climatology published in the 1980s using up to date data records (1971–2017). The weather systems that have been identified to have caused the Mahalapye storm are the surface low and westerly trough. The highest amount of rainfall associated with the storm was 126 mm. Station to station rainfall variability was large as reflected by a huge rainfall range of 106 mm. The country’s updated rainfall climatology based on up to date records range from 330 to 600 mm per annum which is in accord with previous studies in terms of distribution, but the highest annual mean rainfall computed in this study is relatively lower. This study is crucial for improving forecasting of the country’s weather and climate.

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