December in San Pedro de Atacama is the warmest month of the year. In December, the weather in San Pedro de Atacama is typically warm. Average daily high temperature in December is about 21 degrees above zero. On average, San Pedro de Atacama has 20 sunny, 8 partly cloudy, 2 rainy, and 1 cloudy day in December. The rains are usually light. December as well as October and November is considered the most comfortable time to visit San Pedro de Atacama.