October Weather in Portland, United States

Last updated: June 24, 2025

In October, the average temperature in Portland, United States hovers around 10°C (50°F). However, be prepared for a range; temperatures can dip to a chilly -5°C (22°F) or climb to a warm 29°C (85°F). Expect about 119 mm (4.7 in) of precipitation spread over 12 days, contributing to an average humidity of 79%. Be ready for a mix of weather!

October Temperature in Portland

In October in Portland, the average temperature is 10°C (50°F), with maximums reaching 29°C (85°F) and minimums dropping as low as -5°C (22°F). This variation in weather means travelers should be prepared for a range of conditions, from warm days to chilly evenings.

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

The chart illustrates October 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, October typically has an average temperature of 10°C (50°F), with highs reaching up to 29°C (85°F) and lows dropping to around -5°C (22°F).

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

October Precipitation in Portland

In Portland in October, the total precipitation amount is 119 mm (4.7 in), falling over a span of 12 days.

October Precipitation Trends in Portland

The chart displays monthly precipitation patterns in Portland, with values for each month alongside October’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how October’s conditions compare to those of other months. In Portland, October typically receives around 119 mm (4.7 inches) of precipitation spread over approximately 12 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

October Humidity in Portland

In Portland in October humidity is 79%. With an average temperature of 10°C (50°F), this humidity feels like a damp chill that seeps into your bones, making outdoor exploration less inviting and requiring layered clothing to stay comfortable while traveling.

October Average Humidity in Portland

This chart illustrates the average monthly humidity levels in Portland, with October’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In October, average humidity in Portland is approximately 79%, offering insight into how humid the weather typically is during this month.

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

October UV Index in Portland

In Portland in October, 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 October

The chart shows the monthly maximum UV Index (UVI) for Portland in October, 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 October, the maximum UV index in Portland typically reaches 5, which falls under the moderate exposure category.

Data source: Portland October 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 October 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 October’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 October’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-7°C (20°F)	38 mm (1.5 inches)	84%	low
February Weather	-6°C (21°F)	54 mm (2.1 inches)	85%	moderate
March Weather	2°C (35°F)	60 mm (2.3 inches)	84%	moderate
April Weather	7°C (45°F)	92 mm (3.6 inches)	83%	very high
May Weather	15°C (59°F)	139 mm (5.5 inches)	75%	very high
June Weather	21°C (70°F)	124 mm (4.9 inches)	79%	very high
July Weather	23°C (74°F)	112 mm (4.4 inches)	75%	very high
August Weather	21°C (70°F)	112 mm (4.4 inches)	69%	very high
September Weather	18°C (64°F)	111 mm (4.4 inches)	74%	very high
October Weather	10°C (50°F)	119 mm (4.7 inches)	79%	moderate
November Weather	1°C (35°F)	53 mm (2.1 inches)	88%	moderate
December Weather	-3°C (27°F)	44 mm (1.7 inches)	82%	low