Riviersonderend normally receives about 307mm of rain per year and because it receives most of its rainfall during winter it has a Mediterranean climate. The chart below (lower left) shows the average rainfall values for Riviersonderend per month. It receives the lowest rainfall (10mm) in December and the highest (40mm) in August. The monthly distribution of average daily maximum temperatures (centre chart below) shows that the average midday temperatures for Riviersonderend range from 16.7°C in July to 27.8°C in January. The region is the coldest during July when the mercury drops to 4.8°C on average during the night. Consult the chart below (lower right) for an indication of the monthly variation of average minimum daily temperatures.