May in Rio Gallegos is the sunniest month of the year. In May, the weather in Rio Gallegos is typically cold. Average daily high temperature in May is about 7 degrees above zero. On average, Rio Gallegos has 12 partly cloudy, 7 sunny, 7 cloudy, and 5 rainy days in May. The rains are usually light. May as well as April, June, July, and August is considered the most uncomfortable time to visit Rio Gallegos.