With a population of around 55,600, Castle Rock sits in Colorado, United States. The city operates in the Mountain Time Zone.
In 2025, Castle Rock recorded an average annual temperature of 49°F — about 0.9°F below the 30-year normal of 50°F. The hottest day reached 96°F in August; the coldest was -18°F in January. Total precipitation was 20 inches (wetter than usual). The wettest month was May.
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