Average Weather in September in Knox City Texas, United States
Daily high temperatures decrease by 9°F, from 93°F to 84°F, rarely falling below 73°F or exceeding 100°F.
Daily low temperatures decrease by 10°F, from 71°F to 61°F, rarely falling below 51°F or exceeding 77°F.
For reference, on July 24, the hottest day of the year, temperatures in Knox City typically range from 75°F to 97°F, while on January 4, the coldest day of the year, they range from 34°F to 56°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 Knox City experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 27% throughout the month.
The clearest day of the month is September 30, with clear, mostly clear, or partly cloudy conditions 74% of the time.
For reference, on February 24, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 42%, while on October 5, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 76%.
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 Knox City, the chance of a wet day over the course of September is essentially constant, remaining around 22% throughout.
For reference, the year's highest daily chance of a wet day is 37% on May 30, and its lowest chance is 8% on January 11.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in Knox City is essentially constant, remaining about 2.2 inches throughout, and rarely exceeding 4.8 inches or falling below 0.3 inches.
The highest average 31-day accumulation is 2.4 inches on September 19.
Average Monthly Rainfall in September
Over the course of September in Knox City, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 59 minutes, implying an average daily decrease of 2 minutes, 2 seconds, and weekly decrease of 14 minutes, 14 seconds.
The shortest day of the month is September 30, with 11 hours, 51 minutes of daylight and the longest day is September 1, with 12 hours, 50 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Knox City is 7:13 AM on September 1 and the latest sunrise is 19 minutes later at 7:33 AM on September 30.
The latest sunset is 8:04 PM on September 1 and the earliest sunset is 40 minutes earlier at 7:24 PM on September 30.
Daylight saving time is observed in Knox City during 2021, 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 6:30 AM and sets 14 hours, 22 minutes later, at 8:52 PM, while on December 21, the shortest day of the year, it rises at 7:39 AM and sets 9 hours, 56 minutes later, at 5:35 PM.
Sunrise & Sunset with Twilight in September
The figure below presents a compact representation of key lunar data for September 2021. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.
Moon Rise, Set & Phases in September
The chance that a given day will be muggy in Knox City is rapidly decreasing during September, falling from 30% to 12% over the course of the month.
For reference, on June 23, the muggiest day of the year, there are muggy conditions 41% of the time, while on December 22, 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 Knox City is gradually increasing during September, increasing from 9.3 miles per hour to 9.8 miles per hour over the course of the month.
For reference, on April 2, the windiest day of the year, the daily average wind speed is 12.2 miles per hour, while on August 23, the calmest day of the year, the daily average wind speed is 9.1 miles per hour.
Average Wind Speed in September
The hourly average wind direction in Knox City throughout September is predominantly from the south, with a peak proportion of 60% on September 1.
Wind Direction in September
The growing season in Knox City typically lasts for 8.1 months (248 days), from around March 15 to around November 18, rarely starting before February 19 or after April 10, and rarely ending before October 31 or after December 6.
The month of September in Knox City 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 Knox City are rapidly increasing during September, increasing by 738°F, from 4,482°F to 5,220°F, over the course of the month.
Growing Degree Days in September
The average daily incident shortwave solar energy in Knox City is gradually decreasing during September, falling by 0.8 kWh, from 6.1 kWh to 5.3 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 Knox City are 33.418 deg latitude, -99.819 deg longitude, and 1,526 ft elevation.
The topography within 2 miles of Knox City is essentially flat, with a maximum elevation change of 85 feet and an average elevation above sea level of 1,523 feet. Within 10 miles is essentially flat (282 feet). Within 50 miles contains only modest variations in elevation (1,496 feet).
The area within 2 miles of Knox City is covered by cropland (85%) and grassland (11%), within 10 miles by cropland (79%) and shrubs (11%), and within 50 miles by shrubs (41%) and grassland (29%).
This report illustrates the typical weather in Knox City, 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 8 weather stations near enough to contribute to our estimation of the temperature and dew point in Knox City.
For each station, the records are corrected for the elevation difference between that station and Knox City 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 Knox City is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Knox City and a given station.
The stations contributing to this reconstruction are: Wilbarger Co (16%, 103 kilometers, northeast); Dyess Air Force Base (15%, 110 kilometers, south); Stephens County Airport (14%, 116 kilometers, southeast); Childress Municipal Airport (13%, 120 kilometers, north); Avenger Field (12%, 121 kilometers, southwest); Graham Municipal Airport (13%, 123 kilometers, east); Kickapoo Downtown Airport (11%, 133 kilometers, east); and Lubbock International Airport (6%, 188 kilometers, west).
Time zones for airports and weather stations are provided by AskGeo.com .