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Weather & Climate in Jefferson borough (York County), PA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Jefferson borough (York County) experiences four distinct seasons with an average annual temperature of 54°F (12°C). Winters average 32°F in January while summers reach 75°F in July. The area gets 293 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 47.9 inches (wetter than the 38-inch national average). The area receives 34.1 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 40. The city sits at an elevation of 735 feet.
Temperature
32°F Jan (-0°C)
75°F Jul (24°C)
| Annual Average | 53.7°F |
| 1% below US avg | |
| January Average | 32°F (-0°C) |
| July Average | 75°F (24°C) |
| Sunny Days | 293 days/yr |
Geography
| Elevation | 735 ft (224 m) |
| Area | 0.2 sq mi (0.6 km²) |
| Population Density | 866/sq mi |
| Coordinates | 39.8123°N, 76.8430°W |
| Timezone | America/New_York |
| County | York County County |
| Nearest Airport | Gettysburg Regional (GTY) 23 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 40.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 90.4 / 100 |
| Social Vulnerability | 17.1 / 100 |
| Community Resilience | 83.5 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Relatively Moderate |
| Earthquake | Relatively Low |
| Wildfire | Very Low |
| Flood | Relatively High |
| Hail | Very Low |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Moderate |
| Winter Weather | Very High |
| Lightning | Relatively High |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Moderate |
| Landslide | Relatively Low |
| Avalanche | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
27 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.6.
| Jan 16, 1994 | 2 km W of Sinking Spring, Pennsylvania | M4.6 | 90 km | 5 km |
| Jan 16, 1994 | 0 km E of Sinking Spring, Pennsylvania | M4.2 | 91 km | 5 km |
| Jul 16, 2010 | 5 km NNW of Barnesville, Maryland | M3.6 | 78 km | 7 km |
| Jun 13, 2019 | 9 km N of Blain, Pennsylvania | M3.4 | 88 km | 27 km |
| Oct 23, 1990 | 3 km W of Hancocks Bridge, New Jersey | M3.2 | 119 km | 10 km |
| Jun 3, 2010 | 4 km ENE of Franklintown, Pennsylvania | M3.1 | 32 km | 2 km |
| Jan 17, 2016 | 3 km NE of Ranson, West Virginia | M3.0 | 101 km | 5 km |
| Nov 14, 1997 | 0 km S of Rothsville, Pennsylvania | M3.0 | 63 km | 5 km |
| Apr 24, 2009 | 1 km S of Franklintown, Pennsylvania | M2.9 | 32 km | 1 km |
| Jan 16, 1994 | 0 km SSE of Sinking Spring, Pennsylvania | M2.9 | 91 km | 5 km |
| Sep 15, 2019 | 5 km ESE of East Berlin, Pennsylvania | M2.8 | 14 km | 5 km |
| May 10, 1993 | 1 km NW of Whitfield, Pennsylvania | M2.8 | 92 km | 5 km |
| Jul 1, 2009 | 3 km ESE of Pennsville, New Jersey | M2.8 | 118 km | 5 km |
| Oct 25, 2009 | 4 km ENE of Franklintown, Pennsylvania | M2.8 | 34 km | 1 km |
| Mar 11, 1995 | 0 km ENE of Landisville, Pennsylvania | M2.7 | 50 km | 5 km |
| Oct 28, 1994 | 1 km E of Mount Vernon, Maryland | M2.7 | 61 km | — |
| Mar 15, 1993 | 5 km W of Columbia, Maryland | M2.7 | 65 km | 5 km |
| Jan 25, 2015 | 4 km ESE of Downingtown, Pennsylvania | M2.6 | 103 km | 2 km |
| Oct 28, 1996 | 2 km W of Reinholds, Pennsylvania | M2.6 | 78 km | 5 km |
| Jun 25, 2021 | 2 km SE of Woodlawn, Maryland | M2.6 | 58 km | 3 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Hurricane History
2 hurricanes (Category 1+) recorded within 500 km since 1980. Strongest on record: Category 2.
| Year | Name | Category | Max Wind | Closest |
| 2011 | Irene | Category 1 | 75 mph | 248 km |
| 1985 | Gloria | Category 2 | 98 mph | 256 km |
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tornado History
443 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 8 fatalities, 272 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jul 14, 2004 | EF3 | 57 km | 7.5 mi | 0 |
| Sep 24, 2001 | EF3 | 99 km | 17.5 mi | 2 |
| Jul 19, 1996 | EF3 | 37 km | 2.2 mi | 0 |
| Jul 27, 1994 | EF3 | 91 km | 4.0 mi | 0 |
| May 22, 1983 | EF3 | 37 km | 2.0 mi | 0 |
| Jun 7, 1980 | EF3 | 20 km | 1.5 mi | 0 |
| Jun 18, 1970 | EF3 | 80 km | 1.9 mi | 1 |
| Jun 9, 1961 | EF3 | 71 km | 0.1 mi | 0 |
| Apr 16, 1961 | EF3 | 64 km | 0.1 mi | 0 |
| Apr 5, 1952 | EF3 | 12 km | 17.5 mi | 0 |
| Nov 4, 1950 | EF3 | 75 km | 15.9 mi | 0 |
| Sep 1, 2021 | EF2 | 75 km | 5.9 mi | 0 |
| May 28, 2019 | EF2 | 88 km | 3.1 mi | 0 |
| Apr 19, 2019 | EF2 | 86 km | 2.9 mi | 0 |
| Nov 2, 2018 | EF2 | 59 km | 5.5 mi | 0 |
| Feb 24, 2016 | EF2 | 73 km | 4.9 mi | 0 |
| May 23, 2011 | EF2 | 98 km | 4.7 mi | 0 |
| Apr 28, 2011 | EF2 | 33 km | 2.6 mi | 0 |
| Apr 28, 2011 | EF2 | 70 km | 1.1 mi | 0 |
| Sep 18, 2004 | EF2 | 42 km | 2.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Tsunami History
1 tsunami recorded within 500 km.
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1840 | PHILADELPHIA, PENNSYLVANIA | Earthquake | — | — | 140 km |
Source: NOAA/NCEI Historical Tsunami Database.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 32°F (-0°C) | 3.2 in | |
| February | 31°F (-0°C) | 2.8 in | Coldest, Driest |
| March | 41°F (5°C) | 3.6 in | |
| April | 51°F (10°C) | 3.5 in | |
| May | 61°F (16°C) | 4.4 in | Wettest |
| June | 69°F (21°C) | 4.1 in | |
| July | 75°F (24°C) | 3.8 in | Warmest |
| August | 72°F (22°C) | 3.6 in | |
| September | 66°F (19°C) | 4.1 in | |
| October | 54°F (12°C) | 3.5 in | |
| November | 44°F (7°C) | 3.6 in | |
| December | 35°F (1°C) | 3.4 in |
Jefferson borough (York County) has a seasonal temperature swing of 43°F / from 31°F in February to 75°F in July. Total annual precipitation is 43.3 inches, with May being the wettest month (4.4") and February the driest (2.8").