This report describes the typical weather at the Troutdale Airport (Portland, Oregon, United States) weather station over the course of an average June. 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 June is characterized by rising daily high temperatures, with daily highs increasing from 70°F to 76°F over the course of the month, exceeding 88°F or dropping below 60°F only one day in ten.
Over the course of June, the length of the day is essentially constant. The shortest day of the month is June 1 with 15:28 hours of daylight; the longest day is June 17 with 15:42 hours of daylight.
The earliest sunrise is at 5:20am on June 17; the latest sunset is at 9:03pm on June 23; the latest sunrise is at 5:24am on June 30; the earliest sunset is at 8:52pm on June 1.
Daylight savings time is observed in 2012 but it neither starts nor ends in June, so the entire month is in daylight time.
The median cloud cover ranges from 57% (partly cloudy) to 79% (partly cloudy). The trend is for the sky to be clearing rapidly with the median cloud cover decreasing by 22% from the start to the end of the month.
On June 30, the clearest day of the month, the sky is clear, mostly clear, or partly cloudy 40% of the time, and overcast or mostly cloudy 40% of the time.
On June 1, the cloudiest day of the month, the sky is overcast, mostly cloudy, or partly cloudy 54% of the time, and clear or mostly clear 26% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around June 1, occurring in 41% of days. Precipitation is least likely around June 30, occurring in 28% of days.
Throughout June, the most common forms of precipitation are light rain, moderate rain, and thunderstorms.
Light rain is the most severe precipitation observed during 63% of those days with precipitation. It is most likely around June 1, when it is observed during 26% of all days.
Moderate rain is the most severe precipitation observed during 19% of those days with precipitation. It is most likely around June 3, when it is observed during 8% of all days.
Thunderstorms are the most severe precipitation observed during 11% of those days with precipitation. They are most likely around June 7, when it is observed during 4% of all days.
Either snow is exceptionally unlikely to fall at this location in June or this station does not reliably report precipitation types.
The relative humidity typically ranges from 43% (comfortable) to 91% (very humid) over the course of a typical June, rarely dropping below 27% (dry) and reaching as high as 100% (very humid).
The air is driest around June 29, at which time the relative humidity drops below 51% (mildly humid) three days out of four; it is most humid around June 1, rising above 86% (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 June, the dew point typically varies from 45°F (dry) to 56°F (comfortable) and is rarely below 39°F (dry) or above 61°F (comfortable).
The time of the month between June 1 and June 30 is the most comfortable, with dew points that are neither too dry nor too muggy.
Over the course of June typical wind speeds vary from 0 mph to 11 mph (calm to gentle breeze), rarely exceeding 16 mph (moderate breeze).
The highest average wind speed of 5 mph (light breeze) occurs around June 1, at which time the average daily maximum wind speed is 11 mph (gentle breeze).
The lowest average wind speed of 5 mph (light breeze) occurs around June 30, at which time the average daily maximum wind speed is 10 mph (gentle breeze).