Average Weather in January in Jeffersontown Kentucky, United States
In Jeffersontown, the month of January is characterized by essentially constant daily high temperatures, with daily highs around 42°F throughout the month, rarely exceeding 59°F or dropping below 26°F. The lowest daily average high temperature is 42°F on January 16.
Daily low temperatures are around 28°F, rarely falling below 11°F or exceeding 44°F. The lowest daily average low temperature is 27°F on January 29.
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 January
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on January. 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 January
The month of January in Jeffersontown experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 57% throughout the month. The highest chance of overcast or mostly cloudy conditions is 58% on January 3.
The clearest day of the month is January 24, with clear, mostly clear, or partly cloudy conditions 43% 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 Categories in January
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 January is essentially constant, remaining around 25% throughout.
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.
Over the course of January in Jeffersontown, the chance of a day with only rain decreases from 21% to 18%, the chance of a day with mixed snow and rain remains an essentially constant 3% throughout, and the chance of a day with only snow remains an essentially constant 2% throughout.
Probability of Precipitation in January
The average sliding 31-day rainfall during January in Jeffersontown is gradually decreasing, starting the month at 3.0 inches, when it rarely exceeds 5.0 inches or falls below 0.8 inches, and ending the month at 2.6 inches, when it rarely exceeds 4.8 inches or falls below 0.9 inches.
The lowest average 31-day accumulation is 2.5 inches on January 25.
Average Monthly Rainfall in January
We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. As with rainfall, we consider the liquid-equivalent snowfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day liquid-equivalent snowfall during January in Jeffersontown is essentially constant, remaining about 0.3 inches throughout, and rarely exceeding 0.8 inches or falling to 0.0 inches.
Average Monthly Liquid-Equivalent Snowfall in January
Over the course of January in Jeffersontown, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 42 minutes, implying an average daily increase of 1 minute, 24 seconds, and weekly increase of 9 minutes, 51 seconds.
The shortest day of the month is January 1, with 9 hours, 34 minutes of daylight and the longest day is January 31, with 10 hours, 17 minutes of daylight.
Hours of Daylight and Twilight in January
The latest sunrise of the month in Jeffersontown is 7:59 AM on January 5 and the earliest sunrise is 11 minutes earlier at 7:47 AM on January 31.
The earliest sunset is 5:33 PM on January 1 and the latest sunset is 31 minutes later at 6:04 PM on January 31.
Daylight saving time is observed in Jeffersontown during 2017, but it neither starts nor ends during January, so the entire month is in standard 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 January
The chance that a given day will be muggy in Jeffersontown is essentially constant during January, remaining around 0% throughout.
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 January
The average hourly wind speed in Jeffersontown is essentially constant during January, remaining within 0.2 miles per hour of 8.9 miles per hour throughout.
For reference, on February 25, the windiest day of the year, the daily average wind speed is 9.2 miles per hour, while on July 31, the calmest day of the year, the daily average wind speed is 5.2 miles per hour.
Average Wind Speed in January
Wind Direction in January
The growing season in Jeffersontown typically lasts for 6.9 months (211 days), from around April 4 to around November 1, rarely starting before March 16 or after April 22, and rarely ending before October 14 or after November 19.
The month of January in Jeffersontown is reliably fully outside of the growing season.
Time Spent in Various Temperature Bands and the Growing Season in January
The average accumulated growing degree days in Jeffersontown is essentially constant during January, remaining within 7°F of 15°F throughout.
Growing Degree Days in January
The average daily incident shortwave solar energy in Jeffersontown is gradually increasing during January, rising by 0.6 kWh, from 2.0 kWh to 2.6 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in January
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 .