San Bruno Weather in December

San Bruno in December averages 14°C (57°F) during the day and 7°C (45°F) at night. This is the wettest month of the year.

Rainfall in San Bruno in December

With frequent rain showers this month, having an umbrella on hand will keep you dry. Typically around 13 days of rainfall are expected, averaging 113 mm (4.4 in) for the month. The rain this month tends to fall in heavier spells rather than light drizzle. When it rains, showers can be significant.

Temperature in San Bruno in December

In December, San Bruno sees moderate temperatures, with highs of 14°C (57°F). Nights drop to around 7°C (45°F). Even when the weather is stable, mornings and evenings can still feel distinctly cool. With overnight lows of 7°C (45°F), nights are cold. The cold air does make for deep, comfortable sleep if you have enough blankets. The temperatures in December are typically the coolest of the year.

Sunshine in San Bruno in December

The month experiences a moderate amount of sunlight, with 160 hours of sunshine. This provides a nice balance between sunshine and clouds.

Wind Speed in San Bruno in December

Average wind speeds reach 3 m/s (6 knots) in December, creating light breezes that feel pleasant throughout the day. Some days are calmer, while others bring slightly more active breezes.

Average water temperature in December

At 13°C (55°F), the water is cool but manageable for those who don't mind a bit of a shock getting in. Most people adjust after a few minutes.

December in San Bruno 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.

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For a detailed overview over the year and the best time to visit the United States of America, check out our San Bruno's climate page.

San Bruno Temperature in December

Min Temperature 7°C (45°F)  

Max Temperature 14°C (57°F)  

Water Temperature 13°C (55°F) *  

Chance of Rain 43%  

Precipitation 113 mm (4.4 in)  

Rainy days 13 days  

Humidity 78% *  

Windspeed 3 m/s (6 knots) *  

Sunshine 160 hours *  

Percentage Sunshine 54% *  

* Data from: San Francisco, the United States of America (2 KM, 1 Miles).

What to Wear in San Bruno in December

The weather can swing between comfortable and chilly in December, so flexibility is key. Pack a variety of tops, at least one warm layer, and both shorts and long pants. This gives you options no matter what the day brings. Expect heavy rainfall, so bring good rain protection and waterproof bags. Expect water temperatures of around 13°C (55°F), which is definitely too cold for comfortable swimming. Your luggage space is better used for other items. Bring sunglasses since you'll have some sunny periods throughout the month

What To Do in San Bruno in December

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

5/10

Cycling

5/10

Walking

5/10

Camping

3/10

Outdoor sports

9/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit the United States of America, check out our San Bruno's climate page.

More climate data for San Bruno

Temperature Rainfall Sunshine Humidity Wind Speed Water Temp

See the full San Bruno climate overview or explore weather in the United States of America.