Portland Weather in January

Portland gets a little less total rainfall in January compared with the previous two months. But the skies remain cloudy most days, and it still rains more days than not.

This page gives detailed information on the typical January temperature, precipitation, sun, humidity, wind and storms for Portland. The numbers here are historical averages based on climate data gathered near the Portland International Airport, located a few miles from downtown Portland.

Temperature Weather iconTemperature

46 °F January average high 8 °C
37 °F January average low 3 °C
10 days 50 °F max. or more (10 °C)
8 days 32 °F min. or less (0 °C)

On most days in Portland during January the thermometer makes it over 40 degrees Fahrenheit (4 degrees Celsius). On rare days, the temperature has climbed as high as 60 °F (16 °C). Weather as warm as 70 °F (21 °C) is not expected here this month.

Typically on 1 day this month the mercury remains below freezing for the entire day. Most nights, the thermometer dips to 40 °F (4 °C). Although unusual, the temperature can go below 21 °F (-6 °C).

Rainy Weather iconPrecipitation

6.0 in total precipitation 153 mm
20 days of rain or snowfall

Half the time, Portland receives 4.1 to 7.7 inches (105 to 195 mm) of precipitation in January. One in four years has drier weather, while another one in four is wetter.

Snowy Weather iconSnow

1.0 in total snowfall 2.5 cm
1 day with new snow

Most years, Portland receives no fresh snow during January. In one out of four Januarys, the city gets an inch (2.5 cm) or more of fresh snow for the month.

Portland has just one day in January, on average, when the snow accumulated on the ground amounts to an inch (2.5 cm) or more.

Sunny Weather iconSun

28 % sunshine
3 days clear skies

The sun's rays reach the ground in Portland during 28 percent of daylight hours on average in January, for a total of 80 hours in the month. Typically on 3 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in January at Portland lasts for 9 hours and 11 minutes a day on average. The shortest day of the month is the 1st with 8 hours and 47 minutes of daylight. By the end of the month, the days have lengthened to 9:44 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

81 % January average humidity

The relative humidity in Portland during January usually peaks at 85 percent in the morning then drops to 74 percent by mid afternoon.

Local Time1 am4 am7 am10 am1 pm4 pm7 pm10 pm
Humidity % 84 85 85 82 74 74 80 82

Windy Weather iconWind

9.8 mph January wind speed average 15.8 kph

January is the windiest month for Portland.

Stormy Weather iconStorms

4 days rainfall of 0.5 inches (13 mm) or more
0 days with thunderstorms in January

Usually one of Portland's rainstorms drops an inch (25 mm) or more of water in a day on the city. About once a decade, Portland has a January snowstorm that blankets the ground in 3 to 5 inches (8 to 13 cm) of snow.


The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals.

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