December in Sonora is the rainiest and the coldest month of the year. In December, the weather in Sonora is typically warm. Average daily high temperature in December is about 11 degrees above zero. On average, Sonora has 17 sunny, 8 partly cloudy, and 6 rainy days in December. The rains are usually heavy. December as well as January and February is considered the most uncomfortable time to visit Sonora.