January in Foz do Iguaçu is the rainiest and the hottest month of the year. In January, the weather in Foz do Iguaçu is typically hot. Average daily high temperature in January is about 30 degrees above zero. On average, Foz do Iguaçu has 21 rainy and 10 sunny days in January. The rains are usually heavy. January as well as February and December is considered the most uncomfortable time to visit Foz do Iguaçu.