January weather forecast
Seattle, WA

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

Weather in January

January, like December, is a frosty winter month in Seattle, Washington, with an average temperature fluctuating between 36°F (2.2°C) and 45°F (7.2°C).

Temperature

In January, the average high-temperature is almost the same as in December - a still chilly 45°F (7.2°C). In Seattle, in January, the average low-temperature is 36°F (2.2°C).

Humidity

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

Rainfall

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

Snowfall

Months with snowfall in Seattle are January through March and November. January is the first month it typically snows. Throughout January, in the average 1.3 snowfall days, it receives 0.12" (3mm) of snow. Throughout the year, in Seattle, there are 4.8 snowfall days, and 0.94" (24mm) of snow is accumulated.

Ocean temperature

In January, the average ocean temperature is 45.5°F (7.5°C).
Note: 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.

Daylight

In January, the average length of the day is 8h and 58min.
On the first day of January in Seattle, Washington, sunrise is at 7:57 am and sunset at 4:28 pm. On the last day of the month, sunrise is at 7:36 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 exposure to the Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 2 in January interpret into the following advice:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the temperature in January in Seattle?

The average high-temperature, in January, in Seattle, Washington, is 45°F (7.2°C), while the average low-temperature is 36°F (2.2°C).

What is the most humid month in Seattle?

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

What is the average humidity in January in Seattle?

The average relative humidity in January is 85%.

How much does it rain in Seattle in January?

In Seattle, Washington, in January, it is raining for 8.8 days, with typically 0.71" (18mm) of accumulated precipitation.

When does it start to snow in Seattle?

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

What is the ocean temperature in January in Seattle?

In Seattle, Washington, in January, the average water temperature is 45.5°F (7.5°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

What is the average length of the day in January in Seattle?

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

When is the sunrise / 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, sunrise is at 7:36 am and sunset at 5:08 pm PST.

How long on average sun shines in January in Seattle?

The average sunshine duration in January is 4.4h.

What is the month with 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.

What is the UV index reading in January in Seattle?

In Seattle, Washington, the average daily maximum UV index in January is 2. A UV Index estimate of 2, and below, represents a low health threat from unprotected exposure to UV radiation.
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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