July in Lewisville averages a daily high of 35.9°C with nights around 23.5°C. Expect roughly 5 wet days totalling 52mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Lewisville is March–April.
Based on GRAPEVINE DAM, TX US (12.1km), 1995–2024. 24 years of July data.