November in Merthyr Tydfil is the cloudiest month of the year. In November, the weather in Merthyr Tydfil is typically cold. Average daily high temperature in November is about 8 degrees above zero. On average, Merthyr Tydfil has 20 rainy, 6 cloudy, 2 sunny, and 2 partly cloudy days in November. The rains are usually heavy. November as well as January, February, March, and April is considered the most uncomfortable time to visit Merthyr Tydfil.