August in Castle Rock averages a daily high of 28.9°C with nights around 12.6°C. Expect roughly 10 wet days totalling 63.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Castle Rock is May–June.
Based on CASTLE ROCK, CO US (1.7km), 1995–2024. 26 years of August data.