May in Merlo is the rainiest and the cloudiest month of the year. In May, the weather in Merlo is typically warm. Average daily high temperature in May is about 17 degrees above zero. On average, Merlo has 12 sunny, 12 partly cloudy, 6 rainy, and 1 cloudy day in May. The rains are usually moderate. May as well as July is considered the most uncomfortable time to visit Merlo.