In December, the weather in Cayo Largo is typically warm. Average daily high temperature in December is about 26 degrees above zero. On average, Cayo Largo has 17 sunny, 7 partly cloudy, 5 rainy, and 2 cloudy days in December. The rains are usually light. December as well as January, February, March, and April is considered the most comfortable time to visit Cayo Largo.