December in Tumaco is the sunniest and the coldest month of the year. In December, the weather in Tumaco is typically warm. Average daily high temperature in December is about 26 degrees above zero. On average, Tumaco has 30 rainy and 1 sunny day in December. The rains are usually heavy. December as well as January, February, March, and April is considered the most uncomfortable time to visit Tumaco.