January weather forecast
Hillsboro, OR

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The red tree colors of the fall along a road and amid trees in this tranquil neighborhood in Hillsboro, Oregon
The red tree colors of the fall along a road and amid trees in this tranquil neighborhood in Hillsboro, Oregon

Weather in January

January temperatures in Hillsboro, Oregon set the tone for the year with cold highs averaging around 45.3°F (7.4°C) and the lowest typically registering at 34.7°F (1.5°C). The city has a predominantly cloud-filled sky, with humidity at its peak, leading to frequent rainfall. The chilly month witnesses occasional snowfall, transforming the city into a picturesque, winter wonderland. The limited sunshine, averaging around 3.8 hours per day, does little to take away the winter chill. In stark contrast to the dry summer months, the land is moist and contributes to vibrant, green scenery.

Temperature

The average high-temperature for January is a still chilly 45.3°F (7.4°C), closely aligning with the temperature of the preceding month. Throughout January, the temperature in Hillsboro tends to fall to a consistent average low of 34.7°F (1.5°C).

Humidity

January, February, November and December, with an average relative humidity of 85%, are the most humid months in Hillsboro.

Rainfall

January is the month with the most rainfall. Rain falls for 18.8 days and accumulates 4.57" (116mm) of precipitation.

Snowfall

January through March, November and December are months with snowfall in Hillsboro. In Hillsboro, during January, snow falls for 1.6 days and regularly aggregates up to 0.79" (20mm) of snow. In Hillsboro, during the entire year, snow falls for 6.6 days and aggregates up to 4.53" (115mm) of snow.

Daylight

In Hillsboro, the average length of the day in January is 9h and 11min.
On the first day of January in Hillsboro, sunrise is at 7:52 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:34 am and sunset at 5:16 pm PST.

Sunshine

In Hillsboro, the average sunshine in January is 3.8h.

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 estimate of 2, and below, represents a low threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The maximum daily UV index, 2 in January, converts into the following recommendations:
While most people are not greatly affected by extended sun exposure, those with fair skin, babies, and children must always have protection. Exposing oneself to the midday Sun can be harmful due to the strong UV radiation; limit your time outside. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage. Note well! The intensity of the Sun's UV rays can be nearly doubled by snow reflection.
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Frequently asked questions

What are January temperatures in Hillsboro?

During January, Hillsboro experiences an average high-temperature of 45.3°F (7.4°C) and a low-temperature of 34.7°F (1.5°C).

What is the most humid month in Hillsboro?

January, February, November and December, with an average relative humidity of 85%, are most humid months in Hillsboro, Oregon.

What is the average humidity in January in Hillsboro?

The average relative humidity in January in Hillsboro is 85%.

What is the wettest month in Hillsboro?

The month with the most rainfall in Hillsboro is January, when the rain falls for 18.8 days and typically aggregates up to 4.57" (116mm) of precipitation.

How much does it rain in Hillsboro in January?

In Hillsboro, Oregon, in January, during 18.8 rainfall days, 4.57" (116mm) of precipitation is typically accumulated.

How many days does it snow in January in Hillsboro?

In Hillsboro, Oregon, in January, during 1.6 snowfall days, 0.79" (20mm) of snow is typically accumulated.

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

In January, the average day length is 9h and 11min.

When are sunrise and sunset in January in Hillsboro?

In January, on the first day of the month, sunrise is at 7:52 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:34 am and sunset at 5:16 pm PST.

How many hours of sunshine does Hillsboro have in January?

In Hillsboro, Oregon, the average sunshine duration in January is 3.8h.

What is the month with the lowest UV index in Hillsboro?

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

How high is the UV index in January in Hillsboro?

In Hillsboro, the average daily maximum UV index in January is 2. A UV Index reading of 2, and below, represents a low health risk 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
Hillsboro, OR

Average temperature in January - Hillsboro, OR
  • Average high temperature in January: 45.3°F

The warmest month (with the highest average high temperature) is August (81.5°F).
The month with the lowest average high temperature is December (43.9°F).

  • Average low temperature in January: 34.7°F

The month with the highest average low temperature is August (55.4°F).
The coldest month (with the lowest average low temperature) is December (34°F).

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Average pressure in January
Hillsboro, OR

Average pressure in January - Hillsboro, OR
  • Average pressure in January: 30.11"Hg

The month with the highest atmospheric pressure is January (30.11"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).

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Average wind speed in January
Hillsboro, OR

Average wind speed in January - Hillsboro, OR
  • Average wind speed in January: 4.9mph

The windiest month (with the highest average wind speed) is March (5mph).
The calmest months (with the lowest average wind speed) are June, August and September (4.3mph).

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Average humidity in January
Hillsboro, OR

Average humidity in January - Hillsboro, OR
  • Average humidity in January: 85%

The months with the highest relative humidity are January, February, November and December (85%).
The month with the lowest relative humidity is August (64%).

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Average rainfall in January
Hillsboro, OR

Average rainfall in January - Hillsboro, OR
  • Average rainfall in January: 4.57"

The wettest month (with the highest rainfall) is January (4.57").
The driest month (with the least rainfall) is August (0.31").

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Average rainfall days in January
Hillsboro, OR

Average rainfall days in January - Hillsboro, OR
  • Average rainfall days in January: 18.8 days

The month with the highest number of rainy days is March (20.8 days).
The month with the least rainy days is August (4.4 days).

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Average snowfall in January
Hillsboro, OR

Average snowfall in January - Hillsboro, OR
  • Average snowfall in January: 0.79"

The month with the highest snowfall is February (1.81").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in January
Hillsboro, OR

Average snowfall days in January - Hillsboro, OR
  • Average snowfall days in January: 1.6 days

The month with the highest number of snowfall days is February (2.4 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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Average daylight in January /
Average sunshine in January
Hillsboro, OR

Average daylight in January / Average sunshine in January - Hillsboro, OR
  • Average daylight in January: 9h and 1min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in January: 3h and 5min

The month with the most sunshine is August (Average sunshine: 10h and 36min).
The month with the least sunshine is February (Average sunshine: 3h and 42min).

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Average sunshine days in January
Hillsboro, OR

Average sunshine days in January - Hillsboro, OR
  • Average sunshine days in January: 10.8 days

The month with the most sunshine days is July (24.4 days).
The month with the least sunshine days is March (8.5 days).

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Average UV index in January
Hillsboro, OR

Average UV index in January - Hillsboro, OR
  • 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
Hillsboro, OR

Average cloud cover in January - Hillsboro, OR
  • Average cloud cover in January: 61

The month with the most cloud cover is February (Cloud cover 63).
The month with the least cloud cover is August (Cloud cover 25).

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Average visibility in January
Hillsboro, OR

Average visibility in January - Hillsboro, OR
  • Average visibility in January: 4mi

The months with the highest visibility are July, August and September (6mi).
The months with the lowest visibility are January and February (4mi).

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Hillsboro, Oregon, USA

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