Diamond Bar Weather in December

December in Diamond Bar brings pleasant temperatures, with highs of 19°C (66°F) and nights dropping to 7°C (45°F). It's the rainiest month of the year, so come prepared with waterproof gear.

Rainfall in Diamond Bar in December

Expect frequent showers this month, so make sure to have an umbrella to keep yourself dry. Typically around 9 days of rainfall are expected, averaging 84 mm (3.3 in) for the month. When showers do arrive, they tend to be on the heavier side. Worth being prepared even if rain days are not that numerous.

Temperature in Diamond Bar in December

In December, expect pleasant temperatures in Diamond Bar, with highs of 19°C (66°F) and lows of 7°C (45°F) at night. This month falls in the winter season. Temperatures can feel cooler in the morning and evening, so layering is often the best approach. Nights fall to 7°C (45°F), which is cold enough to feel it indoors too. A good thick duvet makes all the difference for a comfortable night's sleep. The weather this month is milder than usual, but still provides a warm and pleasant atmosphere.

Sunshine in Diamond Bar in December

The days are predominantly sunny, with an estimated total of around 205 hours of sunshine. These sun-filled days are perfect for playing sports, visiting parks, or going for a bike ride.

If you prefer dry days with pleasant temperatures, January, February, March, April, May, October and November typically offer the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.