December in Mountain View is the coldest month of the year. In December, the weather in Mountain View is typically warm. Average daily high temperature in December is about 12 degrees above zero. On average, Mountain View has 13 sunny, 12 partly cloudy, 5 rainy, and 1 cloudy day in December. The rains are usually light. December as well as January, February, and March is considered the most uncomfortable time to visit Mountain View.