January weather forecast
Seattle, WA

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Beautiful dusk skyline over the giant skyscrapers of Seattle, Washington
Beautiful dusk skyline over the giant skyscrapers of Seattle, Washington

Weather in January

Winter still holds Seattle in its firm grip as the year takes off, though the climate is milder than some other states. This month, temperatures fluctuate between 36°F (2.2°C) and 45°F (7.2°C), making it relatively mild for a winter month. Outdoor elements characteristic of winter can be expected, including rainfall and occasional snowfall. The precipitation often leaves the city with a beautiful mist that softly blankets the iconic skyline. The winter solstice in the prior month makes for shorter daylight hours, setting a cozy and serene mood that many residents embrace.

Temperature

The arrival of January is marked by an average high-temperature of a still frosty 45°F (7.2°C), bearing a close resemblance to December. Nighttime in Seattle, during January, brings an average low of 36°F (2.2°C), a modest reduction from the day's peak.

Humidity

With an average relative humidity of 85%, January is the most humid month.

Rainfall

In Seattle, in January, during 8.8 rainfall days, 0.71" (18mm) of precipitation is typically accumulated. In Seattle, Washington, during the entire year, the rain falls for 84.2 days and collects up to 5.2" (132mm) of precipitation.

Snowfall

January through March and November are months with snowfall in Seattle. January is the first month it typically snows in Seattle. Throughout January, in the average 1.3 snowfall days, it receives 0.12" (3mm) of snow. In Seattle, during the entire year, snow falls for 4.8 days and aggregates up to 0.94" (24mm) of snow.

Ocean temperature

In January, the average ocean temperature is 45.5°F (7.5°C).
Note: Dipping in 45.5°F (7.5°C) at temperatures less than 50°F (10°C) without proper gear can lead to pronounced cold shock and breathing difficulties.

Daylight

The average length of the day in January in Seattle is 8h and 58min.
On the first day of the month, sunrise is at 7:57 am and sunset at 4:28 pm. On the last day of January, sunrise is at 7:37 am and sunset at 5:08 pm PST.

Sunshine

In Seattle, the average sunshine in January is 4.4h.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a minimal health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: The maximum daily UV index of 2 during January translates into the following directions:
Babies, children, and those with sensitive skin should always avoid extended periods in the sun. Around midday, solar radiation is most harmful; hence, exposure should be limited. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Notice this! Nearly double the intensity of the Sun's UV radiation can be caused by snow reflection.
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Frequently asked questions

What is the temperature in January in Seattle?

The average high-temperature and low-temperature in Seattle during January are 45°F (7.2°C) and 36°F (2.2°C) respectively.

What is the most humid month in Seattle?

January is the most humid month in Seattle, with an average relative humidity of 85%.

What is the average humidity in January in Seattle?

In January, the average relative humidity is 85%.

How many days does it rain in January in Seattle?

In Seattle, during January, the rain falls for 8.8 days and regularly aggregates up to 0.71" (18mm) of precipitation.

When does it start snowing in Seattle?

January is the first month it typically snows in Seattle. Throughout January, in the average 1.3 snowfall days, it receives 0.12" (3mm) of snow.

What is the water temperature in January in Seattle?

In Seattle, the average seawater temperature in January is 45.5°F (7.5°C). Swimming in 45.5°F (7.5°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

How many hours of daylight does Seattle have in January?

The average day length in January in Seattle, Washington, is 8h and 58min.

What time are sunrise and sunset in January in Seattle?

In January, on the first day of the month, sunrise is at 7:57 am and sunset at 4:28 pm. On the last day of the month, in Seattle, Washington, sunrise is at 7:37 am and sunset at 5:08 pm PST.

How long on average sun shines in January in Seattle?

In Seattle, the average sunshine duration in January is 4.4h.

When is the lowest UV index in Seattle?

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Seattle, Washington.

How high is the UV index in January in Seattle?

In Seattle, Washington, the average daily maximum UV index in January is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in January
Seattle, WA

Average temperature in January - Seattle, WA
  • Average high temperature in January: 45°F

The warmest month (with the highest average high temperature) is August (76.3°F).
The month with the lowest average high temperature is December (43.7°F).

  • Average low temperature in January: 36°F

The month with the highest average low temperature is August (54°F).
The coldest month (with the lowest average low temperature) is December (35.1°F).

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Average pressure in January
Seattle, WA

Average pressure in January - Seattle, WA
  • Average pressure in January: 30.1"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).

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Average wind speed in January
Seattle, WA

Average wind speed in January - Seattle, WA
  • Average wind speed in January: 5.2mph

The windiest month (with the highest average wind speed) is March (5.3mph).
The calmest months (with the lowest average wind speed) are July and August (3.5mph).

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Average humidity in January
Seattle, WA

Average humidity in January - Seattle, WA
  • Average humidity in January: 85%

The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is July (69%).

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Average rainfall in January
Seattle, WA

Average rainfall in January - Seattle, WA
  • Average rainfall in January: 0.71"

The wettest month (with the highest rainfall) is December (0.87").
The driest months (with the least rainfall) are July and August (0.12").

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Average rainfall days in January
Seattle, WA

Average rainfall days in January - Seattle, WA
  • Average rainfall days in January: 8.8 days

The month with the highest number of rainy days is November (9.1 days).
The month with the least rainy days is August (2.8 days).

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Average snowfall in January
Seattle, WA

Average snowfall in January - Seattle, WA
  • Average snowfall in January: 0.12"

The month with the highest snowfall is February (0.71").
The months with the least snowfall are April, May, June, July, August, September, October and December (0").

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Average snowfall days in January
Seattle, WA

Average snowfall days in January - Seattle, WA
  • Average snowfall days in January: 1.3 days

The month with the highest number of snowfall days is February (1.9 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average sea temperature in January
Seattle, WA

Average sea temperature in January - Seattle, WA
  • Average sea temperature in January: 45.6°F

The best month for swimming (with the highest average sea temperature) is August (53.5°F).
The coldest month (with the lowest average sea temperature) is February (45.3°F).

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Average daylight in January /
Average sunshine in January
Seattle, WA

Average daylight in January / Average sunshine in January - Seattle, WA
  • Average daylight in January: 9h and 0min

The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).

  • Average sunshine in January: 4h and 2min

The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 18min).

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Average sunshine days in January
Seattle, WA

Average sunshine days in January - Seattle, WA
  • Average sunshine days in January: 18.8 days

The month with the most sunshine days is August (25.9 days).
The month with the least sunshine days is November (16.8 days).

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Average UV index in January
Seattle, WA

Average UV index in January - Seattle, WA
  • Average UV index in January: 2

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in January
Seattle, WA

Average cloud cover in January - Seattle, WA
  • Average cloud cover in January: 55

The month with the most cloud cover is December (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 25).

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Average visibility in January
Seattle, WA

Average visibility in January - Seattle, WA
  • Average visibility in January: 5mi

The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March, November and December (5mi).

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Seattle, Washington, USA

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