Foster City Weather in December

December in Foster City brings moderate temperatures around 14°C (57°F) during the day, dropping to 6°C (43°F) at night, with the most rainfall of the year.

Rainfall in Foster City in December

This month is known for heavy rainfall, so don't forget your umbrella to stay dry. Typically, you can expect about 12 days of rain this month, with 96 mm (3.8 in) on average. When it rains this month, it tends to come down fairly heavily. Showers can be substantial even if they don't last all day.

Temperature in Foster City in December

Daytime highs in Foster City in December reach 14°C (57°F), with nights around 6°C (43°F). The difference between afternoon and evening temperatures is usually noticeable. Nights fall to 6°C (43°F), which is cold enough to feel it indoors too. A good thick duvet makes all the difference for a comfortable night's sleep. December is characterized by some of the mildest temperatures of the year.

Sunshine in Foster City in December

The month brings about 160 hours of sunlight, offering a comfortable mix of sun and overcast.

Wind Speed in Foster City in December

December has wind speeds averaging 3 m/s (6 knots). You can expect comfortable light winds that steadily move flags and feel mild throughout the day. Since this is an average, daily conditions vary from gentle winds to more active breezes.

Average water temperature in December

The water is 13°C (55°F) this month, cool enough to feel refreshing on a warm day, but cold enough that most people won't stay in for long without a wetsuit.

December in Foster City has its charm, but if you're looking for destinations with pleasant temperatures and sunny skies, our weather planner can help you explore other options in the world.