Porterville normally receives about 445mm 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 Porterville per month. It receives the lowest rainfall (9mm) in January and the highest (81mm) in June. The monthly distribution of average daily maximum temperatures (centre chart below) shows that the average midday temperatures for Porterville range from 17°C in July to 30.1°C in February. The region is the coldest during July when the mercury drops to 5.4°C on average during the night. Consult the chart below (lower right) for an indication of the monthly variation of average minimum daily temperatures.