January Weather in Portland, United States

Last updated: June 24, 2025

In January, the average temperature in Portland, United States hovers around 14°C (58°F), with a minimum dip of -4°C (25°F) and a maximum rise of 29°C (85°F). Expect about 39 mm (1.5 in) of precipitation over the course of 5 days, coupled with an average humidity level of 78%.

January Temperature in Portland

In January in Portland, the average temperature is 14°C (58°F). The maximum can reach 29°C (85°F) and the minimum can be as low as -4°C (25°F). This variation in temperature suggests that travelers should pack for both warm and cool weather to fully enjoy their visit.

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 14°C (58°F), with highs reaching up to 29°C (85°F) and lows dropping to around -4°C (25°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 39 mm (1.5 in) spread over a duration of 5 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 39 mm (1.5 inches) of precipitation spread over approximately 5 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 78%. With an average temperature of 14°C (58°F), this humidity feels like a damp embrace, making traveling a bit uncomfortable as the air clings to your skin, causing you to sweat more than usual while exploring.

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 78%, 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 reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in Portland.

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 5, 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	14°C (58°F)	39 mm (1.5 inches)	78%	moderate
February Weather	16°C (60°F)	31 mm (1.2 inches)	82%	very high
March Weather	20°C (68°F)	52 mm (2.1 inches)	79%	very high
April Weather	23°C (73°F)	44 mm (1.7 inches)	82%	extreme
May Weather	26°C (79°F)	138 mm (5.4 inches)	81%	extreme
June Weather	28°C (83°F)	136 mm (5.4 inches)	77%	extreme
July Weather	29°C (84°F)	101 mm (4.0 inches)	78%	extreme
August Weather	29°C (85°F)	81 mm (3.2 inches)	78%	extreme
September Weather	28°C (82°F)	141 mm (5.6 inches)	79%	extreme
October Weather	24°C (75°F)	77 mm (3.0 inches)	77%	very high
November Weather	19°C (66°F)	51 mm (2.0 inches)	78%	high
December Weather	16°C (61°F)	47 mm (1.9 inches)	80%	moderate