August in Wellington is the coldest month of the year. In August, the weather in Wellington is typically warm. Average daily high temperature in August is about 11 degrees above zero. On average, Wellington has 14 rainy, 11 sunny, 4 partly cloudy, and 2 cloudy days in August. The rains are usually heavy. August as well as May, June, July, and September is considered the most uncomfortable time to visit Wellington.