May in Turrialba is the cloudiest month of the year. In May, the weather in Turrialba is typically warm. Average daily high temperature in May is about 23 degrees above zero. On average, Turrialba has 28 rainy and 3 cloudy days in May. The rains are usually heavy. May as well as June, July, August, and September is considered the most uncomfortable time to visit Turrialba.