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Average Weather in Fort Knox Kentucky, United States

In Fort Knox, the summers are warm and muggy, the winters are chilly and wet, and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 27°F to 87°F and is rarely below 11°F or above 94°F.

The hot season lasts for 3.8 months, from May 26 to September 21, with an average daily high temperature above 78°F. The hottest day of the year is July 21, with an average high of 87°F and low of 69°F.

The cold season lasts for 3.1 months, from November 30 to March 1, with an average daily high temperature below 52°F. The coldest day of the year is January 29, with an average low of 27°F and high of 43°F.

Average High and Low Temperature

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

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

Average Hourly Temperature in Fort Knox12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDecfreezingchillycoldcoolcomfortablewarmhot
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < chilly < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Clouds

In Fort Knox, 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 Fort Knox begins around June 16 and lasts for 4.7 months, ending around November 6. On August 23, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 69% of the time, and overcast or mostly cloudy 31% of the time.

The cloudier part of the year begins around November 6 and lasts for 7.3 months, ending around June 16. On January 2, the cloudiest day of the year, the sky is overcast or mostly cloudy 57% of the time, and clear, mostly clear, or partly cloudy 43% of the time.

Cloud Cover

Cloud Cover in Fort Knoxclearercloudiercloudier0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJan 257%Jan 257%Aug 2331%Aug 2331%Jun 1644%Jun 1644%Nov 644%Nov 644%overcastmostly cloudypartly cloudymostly clearclear
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Fort Knox varies throughout the year.

The wetter season lasts 4.6 months, from March 18 to August 6, with a greater than 32% chance of a given day being a wet day. The chance of a wet day peaks at 40% on June 8.

The drier season lasts 7.4 months, from August 6 to March 18. The smallest chance of a wet day is 23% on October 15.

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 40% on June 8.

Daily Chance of Precipitation

Daily Chance of Precipitation in Fort Knoxwetdrydry0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJun 840%Jun 840%Oct 1523%Oct 1523%Jan 126%Jan 126%Mar 1832%Mar 1832%Aug 632%Aug 632%mixedrain
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

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. Fort Knox experiences significant seasonal variation in monthly rainfall.

Rain falls throughout the year in Fort Knox. The most rain falls during the 31 days centered around May 3, with an average total accumulation of 4.8 inches.

The least rain falls around August 23, with an average total accumulation of 2.7 inches.

Average Monthly Rainfall

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Snowfall

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. Fort Knox experiences some seasonal variation in monthly liquid-equivalent snowfall.

The snowy period of the year lasts for 3.6 months, from November 29 to March 16, 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 4, with an average total liquid-equivalent accumulation of 0.4 inches.

The snowless period of the year lasts for 8.4 months, from March 16 to November 29. The least snow falls around July 23, with an average total liquid-equivalent accumulation of 0.0 inches.

Average Liquid-Equivalent Monthly Snowfall

Average Liquid-Equivalent Monthly Snowfall in Fort Knoxsnowsnow0 in1 in2 in3 in4 in5 inJanFebMarAprMayJunJulAugSepOctNovDecFeb 40.4 inFeb 40.4 inJul 230.0 inJul 230.0 inNov 290.1 inNov 290.1 inMar 160.1 inMar 160.1 in
The average liquid-equivalent snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.

Sun

The length of the day in Fort Knox varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 32 minutes of daylight; the longest day is June 21, with 14 hours, 48 minutes of daylight.

Hours of Daylight and Twilight

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 6:21 AM on June 13, and the latest sunrise is 1 hour, 52 minutes later at 8:12 AM on November 4. The earliest sunset is at 5:24 PM on December 6, and the latest sunset is 3 hours, 46 minutes later at 9:10 PM on June 27.

Daylight saving time (DST) is observed in Fort Knox during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.

Sunrise & Sunset with Twilight and Daylight Saving Time

Sunrise & Sunset with Twilight and Daylight Saving Time in Fort Knox2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDecJun 136:21 AMJun 136:21 AM9:10 PMJun 279:10 PMJun 27Dec 65:24 PMDec 65:24 PM8:12 AMNov 48:12 AMNov 4Mar 12DSTMar 12DSTDSTNov 5DSTNov 5daynightnightnightnight
The solar day over the course of the year 2017. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

Humidity

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

Fort Knox experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 4.2 months, from May 19 to September 25, during which time the comfort level is muggy, oppressive, or miserable at least 18% of the time. The muggiest day of the year is July 24, with muggy conditions 71% of the time.

The least muggy day of the year is January 23, when muggy conditions are essentially unheard of.

Humidity Comfort Levels

Humidity Comfort Levels in Fort Knoxmuggy0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecJan 230%Jan 230%Jul 2471%Jul 2471%May 1918%May 1918%Sep 2518%Sep 2518%miserablemiserableoppressiveoppressivemuggymuggyhumidhumidcomfortablecomfortabledrydry
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Fort Knox experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 6.6 months, from October 25 to May 13, with average wind speeds of more than 3.3 miles per hour. The windiest day of the year is February 25, with an average hourly wind speed of 4.3 miles per hour.

The calmer time of year lasts for 5.4 months, from May 13 to October 25. The calmest day of the year is July 31, with an average hourly wind speed of 2.4 miles per hour.

Average Wind Speed

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in Fort Knox varies throughout the year.

The wind is most often from the south for 3.5 months, from March 11 to June 25 and for 4.3 months, from August 14 to December 23, with a peak percentage of 40% on November 14. The wind is most often from the west for 1.6 months, from June 25 to August 14 and for 2.6 months, from December 23 to March 11, with a peak percentage of 38% on July 13.

Wind Direction

Wind Direction in Fort KnoxWSWS0%20%40%60%80%100%JanFebMarAprMayJunJulAugSepOctNovDecwestsoutheastnorth
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Solar Energy

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

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 4.4 months, from April 22 to September 3, with an average daily incident shortwave energy per square meter above 5.7 kWh. The brightest day of the year is July 20, with an average of 6.6 kWh.

The darker period of the year lasts for 3.0 months, from November 8 to February 9, with an average daily incident shortwave energy per square meter below 3.0 kWh. The darkest day of the year is December 23, with an average of 2.0 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy in Fort Knoxbrightdarkdark0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWhJanFebMarAprMayJunJulAugSepOctNovDecJul 206.6 kWhJul 206.6 kWhDec 232.0 kWhDec 232.0 kWhApr 225.7 kWhApr 225.7 kWhSep 35.7 kWhSep 35.7 kWhNov 83.0 kWhNov 83.0 kWhFeb 92.9 kWhFeb 92.9 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Fort Knox are 37.891 deg latitude, -85.964 deg longitude, and 702 ft elevation.

The topography within 2 miles of Fort Knox contains only modest variations in elevation, with a maximum elevation change of 279 feet and an average elevation above sea level of 710 feet. Within 10 miles contains only modest variations in elevation (630 feet). Within 50 miles also contains significant variations in elevation (801 feet).

The area within 2 miles of Fort Knox is covered by artificial surfaces (46%), trees (30%), and cropland (24%), within 10 miles by trees (57%) and cropland (36%), and within 50 miles by trees (49%) and cropland (44%).

Data Sources

This report illustrates the typical weather in Fort Knox, 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 Fort Knox.

For each station, the records are corrected for the elevation difference between that station and Fort Knox 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 Fort Knox is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Fort Knox and a given station.

The stations contributing to this reconstruction are: Godman Army Airfield (99%, 1.0 kilometers, north); Glasgow Municipal Airport (0.3%, 96 kilometers, south); and Stuart Powell Field (0.2%, 111 kilometers, east).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.