Costa Mesa Weather in December

Costa Mesa in December averages 19°C (66°F) during the day and 9°C (48°F) at night. This is the wettest month of the year.

Rainfall in Costa Mesa in December

As the month with the highest rainfall, make sure to have an umbrella to manage the showers. On average, there are about 7 days with rain during this month, averaging 55 mm (2.2 in). Rainfall intensity is on the higher side this month. Expect more substantial showers rather than light, passing rain.

Temperature in Costa Mesa in December

In December, expect pleasant temperatures in Costa Mesa, with highs of 19°C (66°F) and lows of 9°C (48°F) at night. Conditions are often most pleasant around the middle of the day. At 9°C (48°F) overnight, it gets properly cold after dark. On the bright side, cold nights tend to make for excellent sleeping conditions. While this is the time of year with slightly cooler averages, it remains comfortably warm.

Sunshine in Costa Mesa in December

Expect a lot of sunshine this month, with about 205 hours of sun. These sunny conditions add to the overall experience.

Our weather planner can help you find worldwide destinations with pleasant weather during this period. January, February, March, April, May, June, July, August, September, October and November typically offer the best weather for Costa Mesa.