December in Truro is the rainiest and the windiest month of the year. In December, the weather in Truro is typically warm. Average daily high temperature in December is about 10 degrees above zero. On average, Truro has 25 rainy, 3 sunny, 2 cloudy, and 1 partly cloudy day in December. The rains are usually heavy. December as well as January, February, March, and October is considered the most uncomfortable time to visit Truro.