In December, the weather in San Cristobal de las Casas is typically warm. Average daily high temperature in December is about 20 degrees above zero. On average, San Cristobal de las Casas has 18 partly cloudy, 8 sunny, 3 cloudy, and 2 rainy days in December. The rains are usually light. December as well as January, February, and March is considered the most comfortable time to visit San Cristobal de las Casas.