Portland
Oregon, USA
Long-term weather forecast
Long-term weather forecast

December weather forecast and climate
Portland, OR

A colorful autumn view of the outline of Portland City, Oregon, with mountains in the distance
A colorful autumn view of the outline of Portland City, Oregon, with mountains in the distance
December is the coldest month of the year in Portland with the average temperatures in the range of a cold 35.1°F (1.7°C) to a mild 45°F (7.2°C). The chilliest period is around 22nd to 23rd when the nights may dip below freezing.
The heavy rainfall to the tune of 5.5" (139.7mm) spreads over 18 wet days forcing many people to stay indoors for long periods. Light snow of 1.3" (33mm) falls in December, but snow accumulation on the ground is rare. December is the darkest month with just 63 hours of sunshine and the highest humidity of 83%.
Christmas time is chilly but manageable with warm winter coats.

What is the coldest month in Portland?

December is the coldest month in Portland, with an average high-temperature of 45.7°F (7.6°C) and an average low-temperature of 35.2°F (1.8°C).

What is the temperature in December in Portland?

The average high-temperature, in December, in Portland, Oregon, is 45.7°F (7.6°C), while the average low-temperature is 35.2°F (1.8°C).

What is the most humid month in Portland?

December is the most humid month in Portland, with an average relative humidity of 82.7%.

What is the average humidity in December in Portland?

In Portland, Oregon, the average relative humidity in December is 82.7%.

How many days does it rain in December in Portland?

In Portland, during December, the rain falls for 18.6 days and regularly aggregates up to 5.5" (139.4mm) of precipitation.

How many days does it snow in December in Portland?

In Portland, Oregon, during December, snow falls for 1.5 days and regularly aggregates up to 1.3" (33mm) of snow.

What is the month with the shortest days in Portland?

The month with the shortest days is December, with an average of 8.8h of daylight.

How many hours of daylight does Portland have in December?

In Portland, the average length of the day in December is 8.8h.

What is the month with the least sunshine in Portland?

With an average of 2.1h of sunshine, December has the least sunshine of the year in Portland, Oregon.

How many hours of sunshine does Portland have in December?

The average sunshine in December in Portland, Oregon, is 2.1h.

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

January and December, with an average maximum UV index of 1, are months with the lowest UV index in Portland.

How high is the UV index in December in Portland?

The average daily maximum UV index in December in Portland, Oregon, is 1. A UV Index reading of 2, and below, represents a minimal health vulnerability from the exposure to the Sun's UV radiation.
Average temperature in December - Portland, OR
  • Average high temperature in December: 45.6°F

The warmest month (with the highest average high temperature) is August (81.1°F).
The month with the lowest average high temperature is December (45.6°F).

  • Average low temperature in December: 35.2°F

The month with the highest average low temperature is August (58°F).
The coldest month (with the lowest average low temperature) is December (35.2°F).

Average humidity in December - Portland, OR
  • Average humidity in December: 82.7%

The month with the highest relative humidity is December (82.7%).
The month with the lowest relative humidity is July (62.8%).

Average rainfall in December - Portland, OR
  • Average rainfall in December: 5.5"

The wettest month (with the highest rainfall) is November (5.6").
Driest months (with the lowest rainfall) are July and August (0.7").

Average rainfall days in December - Portland, OR
  • Average rainfall days in December: 18.6 days

The month with the highest number of rainy days is November (19 days).
The month with the lowest number of rainy days is August (3.9 days).

Average snowfall in December - Portland, OR
  • Average snowfall in December: 1.3"

The month with the highest snowfall is February (2.1").
Months with the lowest snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in December - Portland, OR
  • Average snowfall days in December: 1.5 days

Months with the highest number of snowfall days are February and December (1.5 days).
Months with the lowest number of snowfall days are April, May, June, July, August, September and October (0 days).

Average daylight in December / Average sunshine in December - Portland, OR
  • Average daylight in December: 8.8h

The month with the longest days is June (Average daylight: 15.6h).
The month with shortest days is December (Average daylight: 8.8h).

  • Average sunshine in December: 2.1h

The month with most sunshine is July (Average sunshine: 10.7h).
The month with least sunshine is December (Average sunshine: 2.1h).

Average UV index in December - Portland, OR
  • Average UV index in December: 1

The month with the highest UV index is July (UV index 8).
Months with the lowest UV index are January and December (UV index 1).