Average Weather in Union Kentucky, United States
In Union, the summers are warm and humid, the winters are very cold and wet, and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 24°F to 86°F and is rarely below 7°F or above 93°F.
Based on the tourism score, the best time of year to visit Union for warm-weather activities is from mid June to late September.
The hot season lasts for 3.8 months, from May 26 to September 20, with an average daily high temperature above 76°F. The hottest day of the year is July 21, with an average high of 86°F and low of 67°F.
The cold season lasts for 3.0 months, from December 1 to March 1, with an average daily high temperature below 48°F. The coldest day of the year is January 29, with an average low of 24°F and high of 39°F.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, 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 Union, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year in Union begins around June 13 and lasts for 4.8 months, ending around November 7. On August 23, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 68% of the time, and overcast or mostly cloudy 32% of the time.
The cloudier part of the year begins around November 7 and lasts for 7.2 months, ending around June 13. On January 2, the cloudiest day of the year, the sky is overcast or mostly cloudy 61% of the time, and clear, mostly clear, or partly cloudy 39% of the time.
Cloud Cover Categories
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Union varies throughout the year.
The wetter season lasts 5.0 months, from March 17 to August 16, with a greater than 32% chance of a given day being a wet day. The chance of a wet day peaks at 41% on May 20.
The drier season lasts 7.0 months, from August 16 to March 17. The smallest chance of a wet day is 22% on January 13.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 41% on May 20.
Daily Chance of Precipitation
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Union experiences significant seasonal variation in monthly rainfall.
Rain falls throughout the year in Union. The most rain falls during the 31 days centered around May 13, with an average total accumulation of 4.2 inches.
The least rain falls around January 28, with an average total accumulation of 2.0 inches.
Average Monthly Rainfall
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. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.
As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Union experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 3.8 months, from November 28 to March 22, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around February 8, with an average total liquid-equivalent accumulation of 0.4 inches.
The snowless period of the year lasts for 8.2 months, from March 22 to November 28. The least snow falls around July 21, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Union varies significantly over the course of the year. In 2018, the shortest day is December 21, with 9 hours, 26 minutes of daylight; the longest day is June 21, with 14 hours, 54 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 6:12 AM on June 14, and the latest sunrise is 1 hour, 56 minutes later at 8:08 AM on November 3. The earliest sunset is at 5:16 PM on December 7, and the latest sunset is 3 hours, 52 minutes later at 9:08 PM on June 27.
Daylight saving time (DST) is observed in Union during 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.
Sunrise & Sunset with Twilight and Daylight Saving Time
Union experiences extreme seasonal variation in the perceived humidity.
The muggier period of the year lasts for 4.0 months, from May 24 to September 23, during which time the comfort level is muggy, oppressive, or miserable at least 14% of the time. The muggiest day of the year is July 19, with muggy conditions 58% of the time.
The least muggy day of the year is December 9, when muggy conditions are essentially unheard of.
Humidity Comfort Levels
The average hourly wind speed in Union experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 6.4 months, from October 27 to May 9, with average wind speeds of more than 5.4 miles per hour. The windiest day of the year is February 25, with an average hourly wind speed of 7.0 miles per hour.
The calmer time of year lasts for 5.6 months, from May 9 to October 27. The calmest day of the year is July 31, with an average hourly wind speed of 3.8 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Union varies throughout the year.
The wind is most often from the south for 2.7 months, from April 3 to June 24 and for 3.6 months, from August 19 to December 8, with a peak percentage of 39% on November 14. The wind is most often from the west for 1.8 months, from June 24 to August 19 and for 3.8 months, from December 8 to April 3, with a peak percentage of 36% on July 13.
Best Time of Year to Visit
To characterize how pleasant the weather is in Union throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Union for general outdoor tourist activities is from mid June to late September, with a peak score in the last week of August.
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Union for hot-weather activities is from late June to late August, with a peak score in the last week of July.
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
The growing season in Union typically lasts for 6.4 months (196 days), from around April 12 to around October 24, rarely starting before March 25 or after April 30, and rarely ending before October 6 or after November 10.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Union should appear around March 22, only rarely appearing before March 7 or after April 7.
Growing Degree Days
The average daily incident shortwave solar energy experiences significant seasonal variation over the course of the year.
The brighter period of the year lasts for 4.1 months, from April 27 to September 1, with an average daily incident shortwave energy per square meter above 5.7 kWh. The brightest day of the year is July 2, with an average of 6.7 kWh.
The darker period of the year lasts for 3.1 months, from November 7 to February 10, with an average daily incident shortwave energy per square meter below 2.8 kWh. The darkest day of the year is December 23, with an average of 1.9 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Union are 38.946 deg latitude, -84.680 deg longitude, and 863 ft elevation.
The topography within 2 miles of Union contains only modest variations in elevation, with a maximum elevation change of 190 feet and an average elevation above sea level of 869 feet. Within 10 miles contains only modest variations in elevation (538 feet). Within 50 miles also contains significant variations in elevation (689 feet).
The area within 2 miles of Union is covered by cropland (44%), artificial surfaces (44%), and trees (12%), within 10 miles by trees (42%) and artificial surfaces (29%), and within 50 miles by cropland (45%) and trees (44%).
This report illustrates the typical weather in Union, 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 Union.
For each station, the records are corrected for the elevation difference between that station and Union 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 Union is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Union and a given station.
The stations contributing to this reconstruction are: Cincinnati/Northern Kentucky International Airport (96%, 11 kilometers, north) and Capital City Airport (4.3%, 87 kilometers, south).
Time zones for aiports and weather stations are provided by AskGeo.com .