Weather & Climate in Green Grass, SD
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Green Grass experiences four distinct seasons with an average annual temperature of 48°F (9°C). Winters average 21°F in January while summers reach 75°F in July. Annual precipitation totals 19.1 inches (drier than the 38-inch national average). The area receives 36.8 inches of snow annually, a moderate snowfall amount. The city sits at an elevation of 2,017 feet.
Temperature
21°F Jan (-6°C)
75°F Jul (24°C)
| Annual Average | 47.8°F |
| 11% below US avg | |
| January Average | 21°F (-6°C) |
| July Average | 75°F (24°C) |
Geography
| Elevation | 2,017 ft (615 m) |
| Area | 8.1 sq mi (21.1 km²) |
| Population Density | 10/sq mi |
| Coordinates | 45.1566°N, 101.2870°W |
| Timezone | America/Chicago |
| County | Corson County County |
| Nearest Airport | Pierre Regional (PIR) 73 miles away |
Precipitation & Snow
Air Quality
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 38.1 / 100 |
| Social Vulnerability | 91.2 / 100 |
| Community Resilience | 2.9 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Very Low |
| Wildfire | Relatively Low |
| Flood | Very Low |
| Hail | Relatively Low |
| Strong Wind | Relatively Low |
| Heat Wave | Very Low |
| Winter Weather | Relatively Moderate |
| Lightning | Very Low |
| Ice Storm | Relatively Low |
| Drought | Very Low |
| Cold Wave | Relatively High |
| Landslide | Very 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: M3.7.
| May 30, 2024 | 38 km NNW of Pierre, South Dakota | M3.7 | 79 km | 15 km |
| Aug 9, 2011 | 2 km S of Fort Pierre, South Dakota | M3.3 | 117 km | 5 km |
| Aug 5, 2022 | 4 km ENE of Draper, South Dakota | M3.2 | 150 km | 9 km |
| Aug 15, 2017 | 8 km E of Agar, South Dakota | M3.0 | 110 km | 5 km |
| Jun 8, 2025 | 19 km NW of Wasta, South Dakota | M2.6 | 149 km | 5 km |
| Jun 16, 2021 | 15 km N of Quinn, South Dakota | M2.6 | 131 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
144 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 17 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Jun 21, 1983 | EF3 | 43 km | 6.0 mi | 0 |
| Jun 20, 1968 | EF3 | 93 km | 8.8 mi | 0 |
| Jun 2, 2024 | EF2 | 89 km | 4.1 mi | 0 |
| Jun 16, 2010 | EF2 | 29 km | 1.4 mi | 0 |
| Jun 16, 2010 | EF2 | 11 km | 0.4 mi | 0 |
| May 24, 2010 | EF2 | 75 km | 8.2 mi | 0 |
| May 24, 2010 | EF2 | 68 km | 22.9 mi | 0 |
| May 24, 2010 | EF2 | 96 km | 22.3 mi | 0 |
| Jul 18, 1986 | EF2 | 84 km | 10.5 mi | 0 |
| May 19, 1974 | EF2 | 92 km | 5.6 mi | 0 |
| May 19, 1974 | EF2 | 99 km | 2.7 mi | 0 |
| Jul 18, 1970 | EF2 | 78 km | 0.1 mi | 0 |
| Aug 12, 1969 | EF2 | 81 km | 6.1 mi | 0 |
| Jul 7, 1969 | EF2 | 75 km | 0.1 mi | 0 |
| Jun 20, 1968 | EF2 | 98 km | 0.1 mi | 0 |
| Jun 8, 1964 | EF2 | 47 km | 3.8 mi | 0 |
| Aug 24, 1960 | EF2 | 90 km | 13.6 mi | 0 |
| Aug 31, 1959 | EF2 | 96 km | 0.1 mi | 0 |
| Apr 19, 1955 | EF2 | 15 km | 0.1 mi | 0 |
| Apr 19, 1955 | EF2 | 93 km | 18.2 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: LAPLANTE (14,777 acres, 2002).
| Year | Name | Acres Burned | Distance |
| 2002 | LAPLANTE | 14,777 | 50 km |
| 1991 | UNNAMED | 14,487 | 62 km |
| 1999 | FAITH | 12,629 | 72 km |
| 2000 | GENO H. | 10,423 | 58 km |
| 2006 | STONE MAN CHURCH | 10,389 | 61 km |
| 2000 | TRIBLE | 9,718 | 98 km |
| 2000 | HOUCK RANCH | 8,746 | 66 km |
| 2006 | BLACK HORSE CREEK | 8,000 | 77 km |
| 1999 | BULLHEAD | 5,606 | 65 km |
| 2006 | KELLY | 5,071 | 82 km |
| 2022 | HWY31 AND 101ST WEST | 4,879 | 95 km |
| 2000 | JENSEN | 4,739 | 35 km |
| 2000 | HAYES | 4,627 | 79 km |
| 2020 | BENT RIM | 3,665 | 29 km |
| 2006 | B WARD 1 | 3,325 | 51 km |
| 2005 | LITTLE BEND | 2,789 | 63 km |
| 2006 | 1804 | 2,778 | 87 km |
| 2000 | PASTURE 9 BURN | 2,768 | 80 km |
| 2012 | MCINTOSH | 2,653 | 88 km |
| 2023 | LITTLE BEND RX | 2,574 | 63 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 21°F (-6°C) | 0.3 in | Coldest, Driest |
| February | 24°F (-4°C) | 0.7 in | |
| March | 35°F (2°C) | 1.0 in | |
| April | 47°F (8°C) | 1.8 in | |
| May | 58°F (14°C) | 3.0 in | |
| June | 68°F (20°C) | 3.7 in | Wettest |
| July | 75°F (24°C) | 2.4 in | Warmest |
| August | 74°F (23°C) | 1.9 in | |
| September | 64°F (18°C) | 1.4 in | |
| October | 49°F (10°C) | 1.9 in | |
| November | 35°F (1°C) | 0.5 in | |
| December | 24°F (-5°C) | 0.6 in |
Green Grass has a seasonal temperature swing of 55°F / from 21°F in January to 75°F in July. Total annual precipitation is 19.1 inches, with June being the wettest month (3.7") and January the driest (0.3").