In August, the weather in Isafjordur is typically cold. Average daily high temperature in August is about 9 degrees above zero. On average, Isafjordur has 15 rainy, 8 cloudy, 5 partly cloudy, and 3 sunny days in August. The rains are usually heavy. August as well as January, February, April, and May is considered the most uncomfortable time to visit Isafjordur.