Average Weather in September in Lewisville Washington, United States
Daily high temperatures decrease by 10°F, from 81°F to 71°F, rarely falling below 60°F or exceeding 92°F.
Daily low temperatures decrease by 5°F, from 55°F to 49°F, rarely falling below 42°F or exceeding 60°F.
For reference, on August 4, the hottest day of the year, temperatures in Lewisville typically range from 58°F to 84°F, while on December 31, the coldest day of the year, they range from 34°F to 43°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 Lewisville experiences rapidly increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 31% to 46%.
The clearest day of the month is September 1, with clear, mostly clear, or partly cloudy conditions 69% of the time.
For reference, on November 30, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 80%, while on August 3, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 80%.
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 Lewisville, the chance of a wet day over the course of September is very rapidly increasing, starting the month at 14% and ending it at 27%.
For reference, the year's highest daily chance of a wet day is 61% on November 19, and its lowest chance is 5% on August 5.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in Lewisville is rapidly increasing, starting the month at 1.3 inches, when it rarely exceeds 2.8 inches or falls below 0.1 inches, and ending the month at 3.1 inches, when it rarely exceeds 6.2 inches or falls below 0.6 inches.
Average Monthly Rainfall in September
Over the course of September in Lewisville, 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, 32 minutes, implying an average daily decrease of 3 minutes, 11 seconds, and weekly decrease of 22 minutes, 14 seconds.
The shortest day of the month is September 30, with 11 hours, 45 minutes of daylight and the longest day is September 1, with 13 hours, 17 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Lewisville is 6:31 AM on September 1 and the latest sunrise is 36 minutes later at 7:07 AM on September 30.
The latest sunset is 7:47 PM on September 1 and the earliest sunset is 56 minutes earlier at 6:51 PM on September 30.
Daylight saving time is observed in Lewisville 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 5:20 AM and sets 15 hours, 44 minutes later, at 9:03 PM, while on December 21, the shortest day of the year, it rises at 7:48 AM and sets 8 hours, 40 minutes later, at 4:28 PM.
Sunrise & Sunset with Twilight in September
The chance that a given day will be muggy in Lewisville is essentially constant during September, remaining around 0% throughout.
For reference, on August 6, 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 Lewisville is essentially constant during September, remaining within 0.1 miles per hour of 4.0 miles per hour throughout.
For reference, on December 29, the windiest day of the year, the daily average wind speed is 5.7 miles per hour, while on July 6, the calmest day of the year, the daily average wind speed is 3.7 miles per hour.
Average Wind Speed in September
Wind Direction in September
Lewisville 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 Lewisville is gradually decreasing during September, falling by 2°F, from 58°F to 56°F, over the course of the month.
Average Water Temperature in September
The growing season in Lewisville typically lasts for 7.4 months (227 days), from around March 31 to around November 13, rarely starting before February 28 or after April 27, and rarely ending before October 21 or after December 9.
The month of September in Lewisville 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 Lewisville are increasing during September, increasing by 360°F, from 1,773°F to 2,133°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in Lewisville is rapidly decreasing during September, falling by 1.8 kWh, from 5.5 kWh to 3.7 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 Lewisville are 45.810 deg latitude, -122.523 deg longitude, and 387 ft elevation.
The topography within 2 miles of Lewisville contains significant variations in elevation, with a maximum elevation change of 656 feet and an average elevation above sea level of 375 feet. Within 10 miles contains significant variations in elevation (2,300 feet). Within 50 miles contains large variations in elevation (10,495 feet).
The area within 2 miles of Lewisville is covered by trees (46%), artificial surfaces (29%), and cropland (21%), within 10 miles by trees (33%) and cropland (32%), and within 50 miles by trees (52%) and shrubs (22%).
This report illustrates the typical weather in Lewisville 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 Lewisville.
For each station, the records are corrected for the elevation difference between that station and Lewisville 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 Lewisville is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Lewisville and a given station.
The stations contributing to this reconstruction are: Pearson Airpark (44%, 23 kilometers, southwest); Scappoose Industrial Airpark (38%, 27 kilometers, west); and Southwest Washington Regional Airport (18%, 45 kilometers, northwest).
Time zones for aiports and weather stations are provided by AskGeo.com .