August in Nanaimo is the sunniest and the warmest month of the year. In August, the weather in Nanaimo is typically warm. Average daily high temperature in August is about 20 degrees above zero. On average, Nanaimo has 16 sunny, 7 rainy, 7 partly cloudy, and 1 cloudy day in August. The rains are usually moderate. August as well as July is considered the most comfortable time to visit Nanaimo.