July in Aosta is the sunniest and the warmest month of the year. In July, the weather in Aosta is typically warm. Average daily high temperature in July is about 13 degrees above zero. On average, Aosta has 22 rainy and 9 sunny days in July. The rains are usually heavy. July as well as April, May, June, and August is considered the most uncomfortable time to visit Aosta.