This report describes the typical weather at the Troutdale Airport (Portland, Oregon, United States) weather station over the course of an average November. It is based on the historical records from 1983 to 2012. Earlier records are either unavailable or unreliable.
Portland, Oregon has a mediterranean climate with dry warm summers and mild winters. The area within 25 mi of this station is covered by forests (77%), built-up areas (10%), croplands (8%), and lakes and rivers (4%).
The month of November is characterized by rapidly falling daily high temperatures, with daily highs decreasing from 57°F to 47°F over the course of the month, exceeding 63°F or dropping below 40°F only one day in ten.
Over the course of November, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 1:07 hours, implying an average day-over-day decrease of 2.2 minutes.
The shortest day of the month is November 30 with 8:59 hours of daylight; the longest day is November 1 with 10:05 hours of daylight.
The earliest sunrise is at 6:54am on November 4; the latest sunset is at 5:55pm on November 1; the latest sunrise is at 7:53am on November 3; the earliest sunset is at 4:27pm on November 30.
Daylight savings time (DST) ends at 1:00am on November 4, 2012, shifting sunrise and sunset to an hour earlier.
The median cloud cover ranges from 90% (mostly cloudy) to 96% (overcast). The trend is for the sky to be becoming cloudier with the median cloud cover increasing by 6% from the start to the end of the month.
On November 15, a representative day, the sky is clear or mostly clear 20% of the time, partly cloudy 4% of the time, and mostly cloudy or overcast 58% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around November 30, occurring in 63% of days. Precipitation is least likely around November 1, occurring in 55% of days.
Throughout November, the most common forms of precipitation are light rain and moderate rain.
Light rain is the most severe precipitation observed during 56% of those days with precipitation. It is most likely around November 14, when it is observed during 34% of all days.
Moderate rain is the most severe precipitation observed during 33% of those days with precipitation. It is most likely around November 29, when it is observed during 21% of all days.
The likelihood of snow falling is highest around November 30, occurring in 4% of days.
Either snow rarely accumulates at this location in November or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 61% (mildly humid) to 94% (very humid) over the course of a typical November, rarely dropping below 42% (comfortable) and reaching as high as 100% (very humid).
The air is driest around November 1, at which time the relative humidity drops below 71% (humid) three days out of four; it is most humid around November 20, rising above 93% (very humid) three days out of four.
Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.
Over the course of a typical November, the dew point typically varies from 33°F (dry) to 46°F (dry) and is rarely below 25°F (dry) or above 54°F (very comfortable).
Over the course of November typical wind speeds vary from 0 mph to 19 mph (calm to fresh breeze), rarely exceeding 29 mph (strong breeze).
The highest average wind speed of 11 mph (gentle breeze) occurs around November 29, at which time the average daily maximum wind speed is 19 mph (fresh breeze).
The lowest average wind speed of 8 mph (gentle breeze) occurs around November 1, at which time the average daily maximum wind speed is 15 mph (moderate breeze).