May in Fortaleza is the warmest month of the year. In May, the weather in Fortaleza is typically warm. Average daily high temperature in May is about 27 degrees above zero. On average, Fortaleza has 25 rainy, 4 sunny, 1 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 Fortaleza.