January Weather in Portland, United States

Last updated: June 24, 2025

In January, the average temperature in Portland, United States hovers around -2°C (29°F), with extremes that can plummet to -25°C (-12°F) or rise to a pleasant 18°C (64°F). Expect about 74 mm (2.9 in) of precipitation spread over 8 days, accompanied by a high average humidity of 85%. Whether bundling up or enjoying a milder day, be prepared for a mix of winter weather!

January Temperature in Portland

In January in Portland, the average temperature is -2°C (29°F). Maximum temperatures can reach 18°C (64°F), while minimums can drop as low as -25°C (-12°F). Travelers should be prepared for a wide range of temperatures and dress accordingly.

January Weather in Portland: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Portland, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Portland, January typically has an average temperature of -2°C (29°F), with highs reaching up to 18°C (64°F) and lows dropping to around -25°C (-12°F).

Data source: Temperature data for Portland generated using information from the Copernicus Climate Change Service.

January Precipitation in Portland

In Portland in January, the precipitation amount is 74 mm (2.9 in) over a period of 8 days.

January Precipitation Trends in Portland

The chart displays monthly precipitation patterns in Portland, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Portland, January typically receives around 74 mm (2.9 inches) of precipitation spread over approximately 8 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

January Humidity in Portland

In Portland in January, humidity is 85%. With an average temperature of -2°C (29°F), this humidity feels like a chilling, damp blanket that clings to your skin, making travel uncomfortable and often prompting an urgent search for warmth and shelter.

January Average Humidity in Portland

This chart illustrates the average monthly humidity levels in Portland, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Portland is approximately 85%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Portland

In Portland in January, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Portland, you can check the information here.

Maximum UV Index Levels in Portland for January

The chart shows the monthly maximum UV Index (UVI) for Portland in January, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In January, the maximum UV index in Portland typically reaches 3, which falls under the moderate exposure category.

Data source: Portland January UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How January Weather in Portland Compares to Other Months

Weather in Portland varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Portland, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Portland, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-2°C (29°F)	74 mm (2.9 inches)	85%	moderate
February Weather	0°C (32°F)	88 mm (3.4 inches)	85%	moderate
March Weather	5°C (42°F)	101 mm (4.0 inches)	86%	high
April Weather	10°C (51°F)	93 mm (3.7 inches)	87%	very high
May Weather	17°C (63°F)	127 mm (5.0 inches)	81%	very high
June Weather	22°C (73°F)	114 mm (4.5 inches)	82%	extreme
July Weather	24°C (76°F)	101 mm (4.0 inches)	81%	very high
August Weather	23°C (74°F)	102 mm (4.0 inches)	79%	very high
September Weather	20°C (69°F)	75 mm (2.9 inches)	78%	very high
October Weather	14°C (57°F)	97 mm (3.8 inches)	81%	high
November Weather	5°C (42°F)	82 mm (3.2 inches)	89%	moderate
December Weather	2°C (35°F)	67 mm (2.7 inches)	86%	low