May in Tumaco is the warmest month of the year. In May, the weather in Tumaco is typically warm. Average daily high temperature in May is about 26 degrees above zero. On average, Tumaco has 28 rainy, 2 cloudy, and 1 partly cloudy day in May. The rains are usually heavy. May as well as January, February, March, and April is considered the most uncomfortable time to visit Tumaco.