SeaTac Weather in December

SeaTac in December sees low daytime temperatures of 8°C (46°F) and nighttime lows of 2°C (36°F). Rainfall is fairly high this month at around 142 mm (5.6 in), so pack a rain jacket to stay dry.

Rainfall in SeaTac in December

Typically, you can expect about 20 days of rain this month, with 142 mm (5.6 in) on average. Expect frequent rainfall this month, and not just light drizzle. When it rains, it tends to come down hard.

Temperature in SeaTac in December

Temperatures in SeaTac in December top out at 8°C (46°F) and drop to 2°C (36°F) overnight. The month of December belongs to the winter season. Expect a cold feel throughout the day, not just in the mornings and evenings. Warm layers are essential. With overnight lows of 2°C (36°F), nights are cold. The cold air does make for deep, comfortable sleep if you have enough blankets. This is usually the coldest month of the year, so be sure to prepare with plenty of winter gear.

Sunshine in SeaTac in December

The month has fewer sunny days, with around 54 hours of sunshine.

Wind Speed in SeaTac in December

Wind speeds average 4 m/s (8 knots) during December. At this speed, expect moderate winds that can raise dust and move small branches. Since this is an average, some days have gentle light winds while others experience stronger breezes that are quite noticeable.

December in SeaTac has its charm. However, if you're seeking pleasant, dry and sunny weather, our weather planner can help you explore other destinations in the world.

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Check the conditions for any month of the year.

• January
• February
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• December

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

SeaTac Temperature in December

Min Temperature 2°C (36°F)  

Max Temperature 8°C (46°F)  

Chance of Rain 66%  

Precipitation 142 mm (5.6 in)  

Rainy days 20 days  

Humidity 80% *  

Windspeed 4 m/s (8 knots) *  

Sunshine 54 hours *  

Percentage Sunshine 20% *  

What to Wear in SeaTac in December

Cold weather calls for smart layering in December. A thermal base layer makes a huge difference in staying warm. Add a wool sweater or fleece, then a wind-resistant outer jacket. Prepare for significant rainfall with proper waterproof clothing and shoes. You can probably leave your sunglasses at home, because sunny days are pretty rare this month.

What To Do in SeaTac in December

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

Swimming

4/10

Cycling

4/10

Walking

4/10

Camping

3/10

Outdoor sports

4/10

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 SeaTac's climate page.

More climate data for SeaTac

Temperature Rainfall Sunshine Humidity Wind Speed

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