August in Thurso is the warmest month of the year. In August, the weather in Thurso is typically warm. Average daily high temperature in August is about 14 degrees above zero. On average, Thurso has 18 rainy, 6 partly cloudy, 4 cloudy, and 3 sunny days in August. The rains are usually heavy. August as well as January, February, March, and April is considered the most uncomfortable time to visit Thurso.