July in St.Lucia is the coldest month of the year. In July, the weather in St.Lucia is typically warm. Average daily high temperature in July is about 22 degrees above zero. On average, St.Lucia has 25 sunny, 3 rainy, and 3 partly cloudy days in July. The rains are usually light. July as well as June and August is considered the most comfortable time to visit St.Lucia.