August in Vasteras is the rainiest month of the year. In August, the weather in Vasteras is typically warm. Average daily high temperature in August is about 19 degrees above zero. On average, Vasteras has 18 rainy, 9 sunny, 3 partly cloudy, and 1 cloudy day in August. The rains are usually heavy. August as well as March, October, November, and December is considered the most uncomfortable time to visit Vasteras.