July in Horsham is the rainiest, the cloudiest, and the coldest month of the year. In July, the weather in Horsham is typically warm. Average daily high temperature in July is about 12 degrees above zero. On average, Horsham has 11 rainy, 10 cloudy, 5 sunny, and 5 partly cloudy days in July. The rains are usually moderate. July as well as August is considered the most uncomfortable time to visit Horsham.