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Weather & Climate in Jefferson, SD
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Jefferson experiences four distinct seasons with an average annual temperature of 49°F (9°C). Winters average 20°F in January while summers reach 74°F in July. The area gets 291 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 28.0 inches (drier than the 38-inch national average). Air quality is rated Good with a median AQI of 35. The city sits at an elevation of 1,115 feet.
Temperature
20°F Jan (-6°C)
74°F Jul (24°C)
| Annual Average | 48.8°F |
| 10% below US avg | |
| January Average | 20°F (-6°C) |
| July Average | 74°F (24°C) |
| Sunny Days | 291 days/yr |
Geography
| Elevation | 1,115 ft (340 m) |
| Area | 0.5 sq mi (1.3 km²) |
| Population Density | 1,406/sq mi |
| Coordinates | 42.6043°N, 96.5661°W |
| Timezone | America/Chicago |
| County | Dakota County County |
| Nearest Airport | Sioux Gateway/Brig General Bud Day Field (SUX) 17 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 35.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 36.0 / 100 |
| Social Vulnerability | 34.2 / 100 |
| Community Resilience | 8.0 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Earthquake | Very Low |
| Wildfire | Relatively Low |
| Flood | Very Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Moderate |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
6 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.6.
| Feb 6, 1996 | 1 km N of Wausa, Nebraska | M3.6 | 81 km | 5 km |
| Aug 9, 1997 | 9 km NW of Clarkson, Nebraska | M3.4 | 103 km | 5 km |
| Jan 4, 2021 | 5 km N of Tyndall, South Dakota | M3.1 | 117 km | 5 km |
| Feb 5, 2025 | 8 km SSE of Tilden, Nebraska | M2.7 | 123 km | 5 km |
| Jun 30, 2021 | 4 km E of Rembrandt, Iowa | M2.7 | 122 km | 10 km |
| Mar 6, 2024 | 6 km SSE of Santee, Nebraska | M2.5 | 104 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
646 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 15 fatalities, 227 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 16, 2014 | EF4 | 86 km | 23.9 mi | 1 |
| Jun 16, 2014 | EF4 | 59 km | 15.8 mi | 0 |
| Jun 16, 2014 | EF4 | 80 km | 11.5 mi | 1 |
| Oct 4, 2013 | EF4 | 48 km | 24.7 mi | 0 |
| Oct 4, 2013 | EF4 | 68 km | 18.3 mi | 0 |
| Jun 23, 2003 | EF4 | 63 km | 13.0 mi | 1 |
| Jul 28, 1986 | EF4 | 34 km | 52.5 mi | 0 |
| Jul 7, 1977 | EF4 | 52 km | 22.6 mi | 0 |
| May 6, 1975 | EF4 | 94 km | 4.1 mi | 0 |
| Jun 7, 1965 | EF4 | 83 km | 7.8 mi | 1 |
| Jun 23, 1952 | EF4 | 61 km | 24.1 mi | 0 |
| Jul 15, 1950 | EF4 | 90 km | 10.0 mi | 0 |
| Jun 17, 2014 | EF3 | 57 km | 4.0 mi | 0 |
| Apr 9, 2011 | EF3 | 79 km | 3.4 mi | 0 |
| Jun 11, 2008 | EF3 | 97 km | 14.2 mi | 4 |
| Jul 5, 1994 | EF3 | 38 km | 1.8 mi | 0 |
| May 27, 1991 | EF3 | 81 km | 6.0 mi | 0 |
| Aug 3, 1981 | EF3 | 89 km | 12.8 mi | 0 |
| May 8, 1979 | EF3 | 37 km | 0.1 mi | 0 |
| Jul 5, 1978 | EF3 | 65 km | 8.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 20°F (-6°C) | 0.5 in | Coldest, Driest |
| February | 25°F (-4°C) | 0.7 in | |
| March | 36°F (2°C) | 2.0 in | |
| April | 49°F (10°C) | 2.7 in | |
| May | 61°F (16°C) | 3.7 in | |
| June | 71°F (22°C) | 3.9 in | Wettest |
| July | 74°F (24°C) | 3.3 in | Warmest |
| August | 73°F (23°C) | 3.0 in | |
| September | 64°F (18°C) | 2.7 in | |
| October | 51°F (11°C) | 2.0 in | |
| November | 35°F (2°C) | 1.3 in | |
| December | 22°F (-6°C) | 0.7 in |
Jefferson has a seasonal temperature swing of 54°F / from 20°F in January to 74°F in July. Total annual precipitation is 26.4 inches, with June being the wettest month (3.9") and January the driest (0.5").