Rio Dell is a city of approximately 3,400 people in California, United States. Located in the Pacific Time Zone at 40.5°N latitude.
In 2025, Rio Dell recorded an average annual temperature of 54°F — about 1.8°F above the 30-year normal of 53°F. The hottest day reached 90°F in September; the coldest was 30°F in February. Total precipitation was 55 inches (wetter than usual). The wettest month was December.
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