This report describes the typical weather at the Ralph Wien Memorial Airport (Kotzebue, Alaska, United States) weather station over the course of an average September. It is based on the historical records from 2001 to 2012. Earlier records are either unavailable or unreliable.
Kotzebue, Alaska has a humid subarctic continental climate with cool summers and no dry season. The area within 25 mi of this station is covered by oceans and seas (64%) and tundra (34%).
The month of September is characterized by rapidly falling daily high temperatures, with daily highs decreasing from 53°F to 40°F over the course of the month, exceeding 58°F or dropping below 34°F only one day in ten.
Over the course of September, the length of the day is very rapidly decreasing. From the start to the end of the month, the length of the day decreases by 3:32 hours, implying an average day-over-day decrease of 7.1 minutes.
The shortest day of the month is September 30 with 11:16 hours of daylight; the longest day is September 1 with 14:49 hours of daylight.
The earliest sunrise is at 7:25am on September 1; the latest sunset is at 10:13pm on September 1; the latest sunrise is at 9:01am on September 30; the earliest sunset is at 8:18pm on September 30.
Daylight saving time is observed in 2012 but it neither starts nor ends in September, so the entire month is in daylight time.
The median cloud cover is 87% (mostly cloudy) and does not vary substantially over the course of the month.
On September 15, a representative day, the sky is clear or mostly clear 18% of the time, partly cloudy 17% of the time, and mostly cloudy or overcast 65% of the time.
The average probability that some form of precipitation will be observed in a given day is 47%, with little variation over the course of the month.
Throughout September, the most common forms of precipitation are light rain, light snow, and moderate rain.
Light rain is the most severe precipitation observed during 61% of those days with precipitation. It is most likely around September 1, when it is observed during 34% of all days.
Light snow is the most severe precipitation observed during 18% of those days with precipitation. It is most likely around September 30, when it is observed during 16% of all days.
Moderate rain is the most severe precipitation observed during 12% of those days with precipitation. It is most likely around September 1, when it is observed during 8% of all days.
The likelihood of snow falling is highest around September 30, occurring in 21% of days.
Either snow rarely accumulates at this location in September or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 63% (mildly humid) to 92% (very humid) over the course of a typical September, rarely dropping below 48% (comfortable) and reaching as high as 98% (very humid).
The air is driest around September 22, at which time the relative humidity drops below 71% (humid) three days out of four; it is most humid around September 1, rising above 89% (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 September, the dew point typically varies from 26°F (dry) to 47°F (dry) and is rarely below 18°F (dry) or above 51°F (very comfortable).
Over the course of September typical wind speeds vary from 3 mph to 18 mph (light air to moderate breeze), rarely exceeding 25 mph (strong breeze).
The highest average wind speed of 12 mph (gentle breeze) occurs around September 16, at which time the average daily maximum wind speed is 17 mph (moderate breeze).
The lowest average wind speed of 11 mph (gentle breeze) occurs around September 26, at which time the average daily maximum wind speed is 16 mph (moderate breeze).