December in Las Vegas is the coldest month of the year. In December, the weather in Las Vegas is typically cold. Average daily high temperature in December is about 5 degrees above zero. On average, Las Vegas has 19 sunny, 8 partly cloudy, 3 snowy, and 1 rainy day in December. The snowfalls are usually light. December as well as January, February, July, and August is considered the most uncomfortable time to visit Las Vegas.