Search: GO! Delmas normally receives about 575mm of rain per year, with most rainfall occuring during summer. The chart below (lower left) shows the average rainfall values for Delmas per month. It receives the lowest rainfall (0mm) in July and the highest (104mm) in January. The monthly distribution of average daily maximum temperatures (centre chart below) shows that the average midday temperatures for Delmas range from 17Â°C in June to 26Â°C in January. The region is the coldest during July when the mercury drops to 0.8Â°C on average during the night.