In August, the weather in Mar del Plata is typically warm. Average daily high temperature in August is about 14 degrees above zero. On average, Mar del Plata has 10 sunny, 10 partly cloudy, 7 rainy, and 4 cloudy days in August. The rains are usually moderate. August as well as June, July, September, and October is considered the most uncomfortable time to visit Mar del Plata.