Average Weather in September in Burien Washington, United States
Daily high temperatures decrease by 8°F, from 75°F to 66°F, rarely falling below 59°F or exceeding 83°F.
Daily low temperatures decrease by 5°F, from 56°F to 51°F, rarely falling below 46°F or exceeding 60°F.
For reference, on August 3, the hottest day of the year, temperatures in Burien typically range from 58°F to 78°F, while on December 23, the coldest day of the year, they range from 37°F to 45°F.
Average High and Low Temperature in September
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on September. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature in September
The month of September in Burien experiences increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 34% to 45%.
The clearest day of the month is September 1, with clear, mostly clear, or partly cloudy conditions 66% of the time.
For reference, on January 19, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 73%, while on August 3, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 75%.
Cloud Cover Categories in September
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Burien, the chance of a wet day over the course of September is very rapidly increasing, starting the month at 16% and ending it at 27%.
For reference, the year's highest daily chance of a wet day is 56% on November 18, and its lowest chance is 8% on August 11.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in Burien is rapidly increasing, starting the month at 1.3 inches, when it rarely exceeds 2.9 inches or falls below 0.1 inches, and ending the month at 2.6 inches, when it rarely exceeds 5.0 inches or falls below 0.6 inches.
Average Monthly Rainfall in September
Over the course of September in Burien, the length of the day is rapidly decreasing. From the start to the end of the month, the length of the day decreases by 1 hour, 38 minutes, implying an average daily decrease of 3 minutes, 22 seconds, and weekly decrease of 23 minutes, 35 seconds.
The shortest day of the month is September 30, with 11 hours, 43 minutes of daylight and the longest day is September 1, with 13 hours, 21 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Burien is 6:28 AM on September 1 and the latest sunrise is 39 minutes later at 7:07 AM on September 30.
The latest sunset is 7:49 PM on September 1 and the earliest sunset is 59 minutes earlier at 6:50 PM on September 30.
Daylight saving time is observed in Burien during 2018, but it neither starts nor ends during September, so the entire month is in daylight saving time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:12 AM and sets 15 hours, 58 minutes later, at 9:10 PM, while on December 21, the shortest day of the year, it rises at 7:54 AM and sets 8 hours, 27 minutes later, at 4:20 PM.
Sunrise & Sunset with Twilight in September
The chance that a given day will be muggy in Burien is essentially constant during September, remaining around 0% throughout.
For reference, on August 4, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in September
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The average hourly wind speed in Burien is essentially constant during September, remaining within 0.2 miles per hour of 3.6 miles per hour throughout.
For reference, on November 30, the windiest day of the year, the daily average wind speed is 5.5 miles per hour, while on August 2, the calmest day of the year, the daily average wind speed is 3.0 miles per hour.
Average Wind Speed in September
Wind Direction in September
Burien is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average surface water temperature in Burien is gradually decreasing during September, falling by 2°F, from 57°F to 55°F, over the course of the month.
Average Water Temperature in September
The growing season in Burien typically lasts for 9.1 months (278 days), from around February 22 to around November 27, rarely starting before January 24 or after March 16, and rarely ending before November 3 or after December 19.
The month of September in Burien is reliably fully within the growing season.
Time Spent in Various Temperature Bands and the Growing Season in September
The average accumulated growing degree days in Burien are increasing during September, increasing by 312°F, from 1,596°F to 1,908°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in Burien is rapidly decreasing during September, falling by 1.6 kWh, from 5.2 kWh to 3.6 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in September
For the purposes of this report, the geographical coordinates of Burien are 47.470 deg latitude, -122.347 deg longitude, and 285 ft elevation.
The topography within 2 miles of Burien contains only modest variations in elevation, with a maximum elevation change of 456 feet and an average elevation above sea level of 249 feet. Within 10 miles contains only modest variations in elevation (830 feet). Within 50 miles contains very significant variations in elevation (13,947 feet).
The area within 2 miles of Burien is covered by artificial surfaces (73%) and water (17%), within 10 miles by artificial surfaces (46%) and water (37%), and within 50 miles by trees (53%) and artificial surfaces (14%).
This report illustrates the typical weather in Burien year round, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Burien.
For each station, the records are corrected for the elevation difference between that station and Burien according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at Burien is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Burien and a given station.
The stations contributing to this reconstruction are: Seattle-Tacoma International Airport (76%, 3.8 kilometers, southeast); King County International Airport (20%, 7 kilometers, northeast); and Bremerton National Airport (4.1%, 32 kilometers, west).
Time zones for aiports and weather stations are provided by AskGeo.com .