July in Guantanamo is the hottest month of the year. In July, the weather in Guantanamo is typically hot. Average daily high temperature in July is about 31 degrees above zero. On average, Guantanamo has 19 rainy and 12 sunny days in July. The rains are usually heavy. July as well as May, June, August, and September is considered the most uncomfortable time to visit Guantanamo.