Last updated: June 24, 2025
In December, the average temperature in Rancho San Diego, United States hovers around 14°C (57°F), with a minimum dipping to 4°C (39°F) and a comfortable maximum reaching 27°C (81°F). Expect some rainfall, as 65 mm (2.5 in) of precipitation is likely over 5 days. Humidity levels remain relatively high, averaging at 74%, making it a month of varied weather conditions.
In December in Rancho San Diego, the average temperature is 14°C (57°F). Maximums can reach 27°C (81°F), and minimums can drop as low as 4°C (39°F). It's a perfect time to explore outdoor activities while enjoying mild weather.
In Rancho San Diego in December, the total precipitation amount is 65 mm (2.5 in) over the course of 5 days.
In Rancho San Diego in December, humidity is 74%. With an average temperature of 14°C (57°F), this humidity feels like a warm, damp blanket wrapping around you, making it slightly uncomfortable for traveling, as you may find yourself quickly sweating and in need of frequent breaks to cool down.
In Rancho San Diego in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Rancho San Diego for better planning.
UV Risk Categories
Weather in Rancho San Diego varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Rancho San Diego, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 13°C (56°F) | 56 mm (2.2 inches) | 72% | moderate |
| February Weather | 13°C (56°F) | 68 mm (2.7 inches) | 77% | high |
| March Weather | 14°C (57°F) | 51 mm (2.0 inches) | 67% | very high |
| April Weather | 16°C (61°F) | 24 mm (0.9 inches) | 56% | very high |
| May Weather | 17°C (63°F) | 21 mm (0.8 inches) | 46% | extreme |
| June Weather | 19°C (67°F) | 2 mm (0.1 inches) | 48% | extreme |
| July Weather | 22°C (72°F) | 3 mm (0.1 inches) | 46% | extreme |
| August Weather | 23°C (74°F) | 1 mm (0.1 inches) | 42% | very high |
| September Weather | 22°C (72°F) | 4 mm (0.1 inches) | 52% | very high |
| October Weather | 20°C (68°F) | 14 mm (0.6 inches) | 58% | high |
| November Weather | 17°C (62°F) | 29 mm (1.1 inches) | 66% | moderate |
| December Weather | 14°C (57°F) | 65 mm (2.5 inches) | 74% | moderate |