December in Tehachapi is the coldest month of the year. In December, the weather in Tehachapi is typically warm. Average daily high temperature in December is about 10 degrees above zero. On average, Tehachapi has 16 sunny, 12 partly cloudy, 2 rainy, and 1 cloudy day in December. The rains are usually light. December as well as January and February is considered the most uncomfortable time to visit Tehachapi.