Average Weather in September in Jeffersontown Kentucky, United States
In Jeffersontown, the month of September is characterized by rapidly falling daily high temperatures, with daily highs decreasing by 10°F, from 84°F to 74°F over the course of the month, and rarely exceeding 91°F or dropping below 64°F.
Daily low temperatures decrease by 11°F, from 65°F to 54°F, rarely falling below 43°F or exceeding 73°F.
For reference, on July 21, the hottest day of the year, temperatures in Jeffersontown typically range from 69°F to 87°F, while on January 29, the coldest day of the year, they range from 27°F to 42°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 Jeffersontown experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 33% throughout the month.
The clearest day of the month is September 21, with clear, mostly clear, or partly cloudy conditions 68% of the time.
For reference, on January 2, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 58%, while on August 23, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 69%.
Cloud Cover in September
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Jeffersontown, the chance of a wet day over the course of September is gradually decreasing, starting the month at 27% and ending it at 25%.
For reference, the year's highest daily chance of a wet day is 41% on May 12, and its lowest chance is 23% on January 14.
Probability of Precipitation in September
The average sliding 31-day rainfall during September in Jeffersontown is gradually increasing, starting the month at 2.7 inches, when it rarely exceeds 4.9 inches or falls below 0.9 inches, and ending the month at 3.0 inches, when it rarely exceeds 5.8 inches or falls below 1.0 inches.
Average Monthly Rainfall in September
Over the course of September in Jeffersontown, 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, 10 minutes, implying an average daily decrease of 2 minutes, 26 seconds, and weekly decrease of 16 minutes, 59 seconds.
The shortest day of the month is September 30, with 11 hours, 49 minutes of daylight and the longest day is September 1, with 12 hours, 59 minutes of daylight.
Hours of Daylight and Twilight in September
The earliest sunrise of the month in Jeffersontown is 7:12 AM on September 1 and the latest sunrise is 25 minutes later at 7:37 AM on September 30.
The latest sunset is 8:11 PM on September 1 and the earliest sunset is 45 minutes earlier at 7:26 PM on September 30.
Daylight saving time is observed in Jeffersontown during 2017, 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 6:19 AM and sets 14 hours, 50 minutes later, at 9:08 PM, while on December 21, the shortest day of the year, it rises at 7:55 AM and sets 9 hours, 30 minutes later, at 5:25 PM.
Sunrise & Sunset with Twilight in September
The chance that a given day will be muggy in Jeffersontown is very rapidly decreasing during September, falling from 46% to 10% over the course of the month.
For reference, on July 24, the muggiest day of the year, there are muggy conditions 66% 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
The average hourly wind speed in Jeffersontown is gradually increasing during September, increasing from 3.1 miles per hour to 3.6 miles per hour over the course of the month.
For reference, on February 25, the windiest day of the year, the daily average wind speed is 5.0 miles per hour, while on July 31, the calmest day of the year, the daily average wind speed is 2.8 miles per hour.
Average Wind Speed in September
Wind Direction in September
The average daily incident shortwave solar energy in Jeffersontown is decreasing during September, falling by 1.1 kWh, from 5.8 kWh to 4.7 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 Jeffersontown are 38.194 deg latitude, -85.564 deg longitude, and 676 ft elevation.
The topography within 2 miles of Jeffersontown contains only modest variations in elevation, with a maximum elevation change of 213 feet and an average elevation above sea level of 675 feet. Within 10 miles also contains only modest variations in elevation (469 feet). Within 50 miles contains only modest variations in elevation (810 feet).
The area within 2 miles of Jeffersontown is covered by artificial surfaces (92%), within 10 miles by artificial surfaces (51%) and trees (25%), and within 50 miles by cropland (49%) and trees (44%).
This report illustrates the typical weather in Jeffersontown 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 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Jeffersontown.
For each station, the records are corrected for the elevation difference between that station and Jeffersontown 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 Jeffersontown is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Jeffersontown and a given station.
Time zones for aiports and weather stations are provided by AskGeo.com .