Portland Weather in October

Portland, Oregon sees a shift during October from summer's dry, sunny weather to winter's wet, cloudy climate.

This page gives detailed information on the typical October temperature, precipitation, sun, humidity, wind and storms for Portland. The numbers here are historical averages based on climate data gathered near the Portland International Airport, located a few miles from downtown Portland.

Temperature Weather iconTemperature

64 °F October average high 18 °C
46 °F October average low 8 °C
22 days 60 °F max. or more (16 °C)
23 days 50 °F min. or less (10 °C)

Usually every October day warms to over 50 degrees Fahrenheit (10 degrees Celsius) in Portland. The city averages 6 days this month when the thermometer reaches into the 70s °F (over 21 °C). October averages one day of temperatures above 80 °F (27 °C).

The thermometer typically drops to 40 °F (4 °C) or below on 5 nights in the month. Frost in October occurs about twice a decade.

Rainy Weather iconRain

4.0 in total precipitation 101 mm
15 days of rain

Half the time, Portland receives 2.6 to 5.0 inches (66 to 128 mm) of rainfall in October. One in four years has drier weather, while another one in four is wetter. None of the precipitation falls as snow this month.

Sunny Weather iconSun

44 % sunshine
5 days clear skies

The sun's rays reach the ground in Portland during 44 percent of daylight hours on average in October, for a total of 149 hours in the month. Typically on 5 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in October at Portland lasts for 10 hours and 54 minutes a day on average. The longest day of the month is the 1st with 11 hours and 41 minutes of daylight. By the end of the month, the days have shortened to 10:09 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

78 % October average humidity

The relative humidity in Portland during October usually peaks at 90 percent in the morning then drops to 60 percent by mid afternoon.

Local Time1 am4 am7 am10 am1 pm4 pm7 pm10 pm
Humidity % 87 90 90 78 63 60 74 82

Windy Weather iconWind

6.5 mph October wind speed average 10.5 kph

October is one of the least windy months in Portland.

Stormy Weather iconStorms

3 days rainfall of 0.5 inches (13 mm) or more
0 days with thunderstorms in October

Some years, Portland gets an inch (25 mm) or more of rain in one day during October. Every few years a thunderstorm shows up at Portland during this month.


The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals.

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