December weather forecast
Portland, OR

A colorful autumn view of the outline of Portland City, Oregon, USA
A colorful autumn view of the outline of Portland City, Oregon, USA

Weather in December

December, the first month of the winter in Portland, is also a frosty month, with an average temperature fluctuating between 44.1°F (6.7°C) and 34.7°F (1.5°C).

Temperature

With an average high-temperature of 44.1°F (6.7°C) and an average low-temperature of 34.7°F (1.5°C), December is the coldest month.

Humidity

January, February and December, with an average relative humidity of 83%, are the most humid months.

Rainfall

The month with the most rainfall is December, when the rain falls for 18.5 days and typically aggregates up to 4.53" (115mm) of precipitation.

Snowfall

January through March, November and December are months with snowfall in Portland. In Portland, Oregon, during December, snow falls for 0.8 days and regularly aggregates up to 0.28" (7mm) of snow. In Portland, during the entire year, snow falls for 6.4 days and aggregates up to 3.94" (100mm) of snow.

Daylight

The month with the shortest days is December, with an average of 8h and 46min of daylight.
On the first day of the month, sunrise is at 7:30 am and sunset at 4:28 pm. On the last day of December, in Portland, sunrise is at 7:50 am and sunset at 4:36 pm PST.

Sunshine

The average sunshine in December is 4.3h.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Portland. A UV Index estimate of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV radiation for average individuals.
Note: The average daily UV index of 2 in December transform into the following instructions:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
[Resources]

FAQ

What is the coldest month in Portland?

December is the coldest month in Portland, with an average high-temperature of 44.1°F (6.7°C) and an average low-temperature of 34.7°F (1.5°C).

What is the most humid month in Portland?

The months with the highest humidity in Portland are January, February and December, with an average relative humidity of 83%.

What is the average humidity in December in Portland?

In Portland, the average relative humidity in December is 83%.

What is the rainiest month in Portland?

December is the month with the most rainfall. Rain falls for 18.5 days and accumulates 4.53" (115mm) of precipitation.

How many days does it rain in December in Portland?

In December, in Portland, Oregon, the rain falls for 18.5 days. Throughout December, 4.53" (115mm) of precipitation is accumulated.

How many days does it snow in December in Portland?

In Portland, Oregon, during December, snow falls for 0.8 days and regularly aggregates up to 0.28" (7mm) of snow.

What is the month with the shortest days in Portland?

With an average of 8h and 46min of daylight, December has the shortest days of the year in Portland, Oregon.

What is the average length of the day in December in Portland?

The average day length in December in Portland, Oregon, is 8h and 46min.

What time are sunrise and sunset in December in Portland?

On the first day of December, sunrise is at 7:30 am and sunset at 4:28 pm. On the last day of the month, sunrise is at 7:50 am and sunset at 4:36 pm PST.

How many hours of sunshine does Portland have in December?

In December, the average sunshine duration in Portland, Oregon, is 4.3h.

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

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

What is the UV index intensity in December in Portland?

The average daily maximum UV index in December is 2. A UV Index reading 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 December
Portland, OR

Average temperature in December - Portland, OR
  • Average high temperature in December: 44.1°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 (44.1°F).

  • Average low temperature in December: 34.7°F

The month with the highest average low temperature is August (55°F).
The coldest month (with the lowest average low temperature) is December (34.7°F).

[Resources]

Average pressure in December
Portland, OR

Average pressure in December - Portland, OR
  • Average pressure in December: 30.1"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).

[Resources]

Average wind speed in December
Portland, OR

Average wind speed in December - Portland, OR
  • Average wind speed in December: 5.5mph

The windiest month (with the highest average wind speed) is January (5.8mph).
The calmest month (with the lowest average wind speed) is August (3.9mph).

[Resources]

Average humidity in December
Portland, OR

Average humidity in December - Portland, OR
  • Average humidity in December: 83%

The months with the highest relative humidity are January, February and December (83%).
The month with the lowest relative humidity is August (63%).

[Resources]

Average rainfall in December
Portland, OR

Average rainfall in December - Portland, OR
  • Average rainfall in December: 4.53"

The wettest month (with the highest rainfall) is December (4.53").
The driest month (with the least rainfall) is July (0.31").

[Resources]

Average rainfall days in December
Portland, OR

Average rainfall days in December - Portland, OR
  • Average rainfall days in December: 18.5 days

The month with the highest number of rainy days is March (20.4 days).
The month with the least rainy days is July (4.9 days).

[Resources]

Average snowfall in December
Portland, OR

Average snowfall in December - Portland, OR
  • Average snowfall in December: 0.28"

The month with the highest snowfall is March (1.5").
The months with the least snowfall are April, May, June, July, August, September and October (0").

[Resources]

Average snowfall days in December
Portland, OR

Average snowfall days in December - Portland, OR
  • Average snowfall days in December: 0.8 days

The month with the highest number of snowfall days is February (2.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

[Resources]

Average daylight in December /
Average sunshine in December
Portland, OR

Average daylight in December / Average sunshine in December - Portland, OR
  • Average daylight in December: 8h and 46min

The month with the longest days is June (Average daylight: 15h and 38min).
The month with the shortest days is December (Average daylight: 8h and 46min).

  • Average sunshine in December: 4h and 18min

The month with the most sunshine is August (Average sunshine: 10h and 54min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).

[Resources]

Average sunshine days in December
Portland, OR

Average sunshine days in December - Portland, OR
  • Average sunshine days in December: 10.5 days

The months with the most sunshine days are July and August (23.8 days).
The month with the least sunshine days is March (8.3 days).

[Resources]

Average UV index in December
Portland, OR

Average UV index in December - Portland, OR
  • Average UV index in December: 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).

[Resources]

Average cloud cover in December
Portland, OR

Average cloud cover in December - Portland, OR
  • Average cloud cover in December: 56

The month with the most cloud cover is February (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 23).

[Resources]

Average visibility in December
Portland, OR

Average visibility in December - Portland, OR
  • Average visibility in December: 5mi

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

[Resources]

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location
* you will be automatically redirected to the weather forecast for your location