December in Cayo Santa Maria is the sunniest month of the year. In December, the weather in Cayo Santa Maria is typically warm. Average daily high temperature in December is about 25 degrees above zero. On average, Cayo Santa Maria has 24 sunny, 4 rainy, and 3 partly cloudy days in December. The rains are usually moderate. December as well as January, February, March, and April is considered the most comfortable time to visit Cayo Santa Maria.