January Weather in Portland, United States

Last updated: June 24, 2025

In January, the average temperature in Portland, United States hovers around -12°C (10°F), with extremes ranging from a chilling -38°C (-36°F) to a mild 4°C (39°F). Expect about 18 mm (0.7 in) of precipitation over 3 days, contributing to a high average humidity of 90%. Stay warm and prepared for winter conditions!

January Temperature in Portland

In January in Portland, the average temperature is -12°C (10°F), with a maximum reaching 4°C (39°F) and a minimum that can plummet to -38°C (-36°F). Travelers should be well-prepared for extreme cold conditions 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 -12°C (10°F), with highs reaching up to 4°C (39°F) and lows dropping to around -38°C (-36°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 18 mm (0.7 in) over a span of 3 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 18 mm (0.7 inches) of precipitation spread over approximately 3 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 90%. With an average temperature of -12°C (10°F), this humidity feels like an icy blanket enveloping you, making every breath a struggle and travel exhausting as the cold moisture clings to your skin, leaving you yearning for warmth.

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 90%, 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	-12°C (10°F)	18 mm (0.7 inches)	90%	low
February Weather	-13°C (9°F)	19 mm (0.8 inches)	92%	moderate
March Weather	-3°C (27°F)	27 mm (1.1 inches)	85%	moderate
April Weather	4°C (39°F)	41 mm (1.6 inches)	81%	high
May Weather	13°C (56°F)	55 mm (2.2 inches)	75%	very high
June Weather	20°C (69°F)	91 mm (3.6 inches)	79%	very high
July Weather	22°C (72°F)	62 mm (2.4 inches)	76%	very high
August Weather	20°C (68°F)	81 mm (3.2 inches)	78%	very high
September Weather	15°C (60°F)	68 mm (2.7 inches)	77%	high
October Weather	6°C (44°F)	79 mm (3.1 inches)	79%	moderate
November Weather	-2°C (28°F)	21 mm (0.8 inches)	86%	moderate
December Weather	-8°C (18°F)	39 mm (1.5 inches)	86%	low