July in Watervliet is the warmest month of the year. In July, the weather in Watervliet is typically warm. Average daily high temperature in July is about 26 degrees above zero. On average, Watervliet has 19 sunny, 7 partly cloudy, and 5 rainy days in July. The rains are usually moderate. July as well as August and September is considered the most comfortable time to visit Watervliet.