Weather & Climate in Union, KY
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Union experiences four distinct seasons with an average annual temperature of 55°F (13°C). Winters average 31°F in January while summers reach 76°F in July. Annual precipitation totals 45.3 inches. The area receives 23.3 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 43. 80% of days have good air quality. The city sits at an elevation of 905 feet.
Temperature
31°F Jan (-0°C)
76°F Jul (24°C)
| Annual Average | 54.7°F |
| 1% above US avg | |
| January Average | 31°F (-0°C) |
| July Average | 76°F (24°C) |
Geography
| Elevation | 905 ft (276 m) |
| Area | 3.3 sq mi (8.6 km²) |
| Population Density | 1,946/sq mi |
| Coordinates | 38.9469°N, 84.6737°W |
| Timezone | America/New_York |
| County | Boone County County |
| Nearest Airport | Cincinnati/Northern Kentucky International (CVG) 7 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
| Good Days % | 79.6% |
| Unhealthy Days | 1 |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 74.5 / 100 |
| Social Vulnerability | 10.6 / 100 |
| Community Resilience | 71.9 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Hurricane | Very Low |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Low |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Moderate |
| Ice Storm | Relatively Moderate |
| Drought | Very Low |
| Cold Wave | Relatively High |
| Landslide | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
14 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.8.
| Sep 12, 2004 | 4 km NW of Manilla, Indiana | M3.8 | 112 km | 2 km |
| Feb 19, 1995 | 8 km SSE of Rocky Fork Point, Ohio | M3.6 | 106 km | 10 km |
| Sep 8, 1990 | 5 km N of Owingsville, Kentucky | M3.3 | 115 km | 0 km |
| Aug 20, 2015 | 6 km SE of Lawrenceburg, Kentucky | M2.8 | 107 km | 34 km |
| Mar 17, 1999 | 2 km NNE of Ripley, Ohio | M2.8 | 76 km | 0 km |
| May 11, 2025 | 11 km SE of High Bridge, Kentucky | M2.8 | 132 km | 30 km |
| Mar 21, 1990 | 1 km W of Spring Mill, Kentucky | M2.7 | 123 km | 4 km |
| Jan 12, 2023 | 4 km E of Burgin, Kentucky | M2.6 | 133 km | 35 km |
| Aug 4, 2023 | 11 km ENE of Lancaster, Kentucky | M2.6 | 143 km | 17 km |
| May 11, 2015 | 5 km ESE of Maysville, Kentucky | M2.6 | 93 km | 11 km |
| Jul 23, 2013 | 6 km NNE of Germantown, Kentucky | M2.6 | 68 km | 4 km |
| Jan 21, 2018 | 8 km SSE of High Bridge, Kentucky | M2.6 | 132 km | 11 km |
| Jan 28, 2024 | 3 km SW of Old Washington, Kentucky | M2.5 | 83 km | 15 km |
| Jan 4, 1999 | 9 km WNW of Mount Sterling, Kentucky | M2.5 | 111 km | 10 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
459 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF5. Total: 79 fatalities, 2,984 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 3, 1974 | EF5 | 18 km | 20.8 mi | 3 |
| Apr 3, 1974 | EF5 | 93 km | 31.3 mi | 36 |
| May 27, 2019 | EF4 | 99 km | 18.2 mi | 0 |
| Mar 2, 2012 | EF4 | 18 km | 9.9 mi | 4 |
| Sep 20, 2000 | EF4 | 98 km | 9.0 mi | 1 |
| Apr 9, 1999 | EF4 | 41 km | 10.0 mi | 4 |
| Nov 22, 1992 | EF4 | 52 km | 26.7 mi | 1 |
| Jun 2, 1990 | EF4 | 37 km | 33.0 mi | 0 |
| Apr 3, 1974 | EF4 | 31 km | 19.8 mi | 2 |
| Apr 3, 1974 | EF4 | 93 km | 35.6 mi | 4 |
| Apr 3, 1974 | EF4 | 55 km | 27.1 mi | 0 |
| Apr 23, 1968 | EF4 | 39 km | 24.1 mi | 1 |
| Apr 23, 1968 | EF4 | 41 km | 78.7 mi | 6 |
| Mar 2, 2012 | EF3 | 30 km | 20.4 mi | 3 |
| Mar 2, 2012 | EF3 | 65 km | 8.7 mi | 3 |
| Feb 28, 2011 | EF3 | 79 km | 2.3 mi | 0 |
| Oct 18, 2007 | EF3 | 93 km | 4.8 mi | 0 |
| May 27, 2004 | EF3 | 97 km | 3.0 mi | 0 |
| May 10, 2003 | EF3 | 90 km | 25.0 mi | 0 |
| Apr 9, 1999 | EF3 | 72 km | 3.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: JPG 09 1 (6,113 acres, 1998).
| Year | Name | Acres Burned | Distance |
| 1998 | JPG 09 1 | 6,113 | 65 km |
| 2005 | RX BURNPLAN AREA 2-06 | 5,054 | 64 km |
| 2007 | UNITS 8-9 2008 | 4,316 | 66 km |
| 2006 | UNIT 19 06 WUI | 3,412 | 66 km |
| 2003 | WUI 3 03 | 3,372 | 66 km |
| 2010 | WUI UNIT 28K | 3,230 | 65 km |
| 1999 | UNNAMED | 3,122 | 67 km |
| 2002 | UNIT 8 | 2,753 | 67 km |
| 2005 | UNIT 3 05 | 2,511 | 67 km |
| 2001 | 01 UNIT 16 | 2,361 | 62 km |
| 2011 | WUI UNITS 0 AND 1 2011 | 2,215 | 67 km |
| 2004 | UNIT 19 | 2,004 | 67 km |
| 2003 | UNIT 8 03 | 1,971 | 67 km |
| 2008 | FY 09 UNIT 42 RX FALL 2008 | 1,942 | 66 km |
| 2000 | JPG 14 | 1,908 | 65 km |
| 2003 | UNIT 16 03 | 1,809 | 63 km |
| 2002 | UNIT 9 | 1,485 | 65 km |
| 1995 | UNNAMED | 1,462 | 66 km |
| 2010 | TRACER | 1,408 | 66 km |
| 2007 | UNNAMED | 1,334 | 63 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 31°F (-0°C) | 3.3 in | Coldest |
| February | 35°F (2°C) | 3.2 in | |
| March | 44°F (6°C) | 4.2 in | |
| April | 55°F (13°C) | 4.5 in | |
| May | 64°F (18°C) | 4.7 in | |
| June | 72°F (22°C) | 4.8 in | Wettest |
| July | 76°F (24°C) | 3.8 in | Warmest |
| August | 75°F (24°C) | 3.4 in | |
| September | 68°F (20°C) | 3.1 in | Driest |
| October | 56°F (13°C) | 3.4 in | |
| November | 44°F (7°C) | 3.2 in | |
| December | 36°F (2°C) | 3.7 in |
Union has a seasonal temperature swing of 45°F / from 31°F in January to 76°F in July. Total annual precipitation is 45.3 inches, with June being the wettest month (4.8") and September the driest (3.1").