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). Expect minimums plunging to -18°C (0°F), while maximums can reach a milder 13°C (56°F). Be prepared for precipitation totaling 98 mm (3.9 in) over approximately 15 days, accompanied by a high average humidity of 91%.

January Temperature in Portland

In January in Portland, the average temperature is -2°C (29°F). The maximum can reach 13°C (56°F), while the minimum can drop as low as -18°C (0°F). Travelers should be prepared for a wide range of temperatures and dress in layers to stay comfortable.

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 13°C (56°F) and lows dropping to around -18°C (0°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 total precipitation amount is 98 mm (3.9 in) spread over 15 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 98 mm (3.9 inches) of precipitation spread over approximately 15 days.

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

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Millimeters (mm) Inches (in)

January Humidity in Portland

In Portland in January, humidity is 91%. With an average temperature of -2°C (29°F), this humidity feels like a chilling embrace that can quickly sap your energy, making outdoor adventures uncomfortable and dampening the joy of exploration.

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 91%, 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 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Portland, you can visit 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 2, which falls under the low 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)	98 mm (3.9 inches)	91%	low
February Weather	-1°C (30°F)	98 mm (3.9 inches)	91%	moderate
March Weather	1°C (34°F)	95 mm (3.7 inches)	88%	high
April Weather	5°C (41°F)	112 mm (4.4 inches)	88%	very high
May Weather	11°C (52°F)	111 mm (4.4 inches)	82%	very high
June Weather	17°C (63°F)	102 mm (4.0 inches)	79%	very high
July Weather	22°C (72°F)	125 mm (4.9 inches)	77%	very high
August Weather	22°C (71°F)	85 mm (3.3 inches)	72%	very high
September Weather	19°C (66°F)	88 mm (3.5 inches)	76%	very high
October Weather	13°C (56°F)	151 mm (5.9 inches)	83%	high
November Weather	6°C (43°F)	125 mm (4.9 inches)	88%	moderate
December Weather	2°C (36°F)	128 mm (5.0 inches)	87%	low