August in Porto-Novo is the coldest month of the year. In August, the weather in Porto-Novo is typically warm. Average daily high temperature in August is about 27 degrees above zero. On average, Porto-Novo has 25 rainy, 5 cloudy, and 1 sunny day in August. The rains are usually heavy. August as well as March, April, May, and June is considered the most uncomfortable time to visit Porto-Novo.