July in Longmont averages a daily high of 32.5°C with nights around 13.9°C. Expect roughly 7 wet days totalling 35.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Longmont is September–October.
Based on LONGMONT 2 ESE, CO US (2.1km), 1995–2024. 17 years of July data.