Weather & Climate in Hermosa, SD

Temperature, precipitation, air quality, natural hazards, and monthly weather data.

Hermosa experiences four distinct seasons with an average annual temperature of 46°F (8°C). Winters average 28°F in January while summers reach 69°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 24.1 inches (drier than the 38-inch national average). The area receives 59.3 inches of snow annually, making winter weather a significant factor for residents. Air quality is rated Good with a median AQI of 35. The city sits at an elevation of 3,324 feet.

Temperature

28°F Jan (-2°C) 69°F Jul (21°C)

Annual Average	45.7°F
	15% below US avg
January Average	28°F (-2°C)
July Average	69°F (21°C)
Sunny Days	291 days/yr

Geography

Elevation	3,324 ft (1,013 m)
Area	0.5 sq mi (1.2 km²)
Population Density	340/sq mi
Coordinates	43.8399°N, 103.1905°W
Timezone	America/Chicago
County	Custer County County
Nearest Airport	Rapid City Regional (RAP) 16 miles away

Precipitation & Snow

Annual Rainfall 24.1"

37% below US avg

Snowfall 59.3"

Wettest Month (May) 3.19"

Driest Month (Jan) 0.31"

Air Quality

AQI Median	35.0
Rating	Good

Natural Hazard Risk

Overall Risk	Very Low
Risk Score	16.4 / 100
Social Vulnerability	10.6 / 100
Community Resilience	47.0 / 100

Hazard Breakdown

Tornado	Very Low
Earthquake	Very Low
Wildfire	Relatively Moderate
Flood	Very Low
Hail	Relatively Low
Strong Wind	Very Low
Heat Wave	Very Low
Winter Weather	Relatively Low
Lightning	Relatively Low
Ice Storm	Very Low
Drought	Very Low
Cold Wave	Very Low
Landslide	Very 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: M4.0.

May 25, 2003	10 km SSW of Martin, South Dakota	M4.0	140 km	5 km
Jan 28, 1990	8 km N of Manderson-White Horse Creek, South Dakota	M4.0	81 km	5 km
Apr 9, 1996	34 km SW of Edgemont, South Dakota	M3.7	113 km	5 km
Feb 6, 1996	13 km WNW of Hill City, South Dakota	M3.7	46 km	5 km
Mar 9, 2025	7 km W of Fairburn, South Dakota	M3.6	20 km	5 km
Dec 12, 2013	10 km WSW of Hermosa, South Dakota	M3.5	11 km	5 km
Mar 26, 2021	10 km E of Edgemont, South Dakota	M3.4	72 km	5 km
Mar 2, 1990	7 km N of Manderson-White Horse Creek, South Dakota	M3.2	82 km	5 km
May 3, 1996	32 km SSW of Edgemont, South Dakota	M3.1	111 km	5 km
Feb 7, 2007	11 km WSW of Wasta, South Dakota	M3.1	53 km	5 km
Jun 18, 1998	23 km S of Chadron, Nebraska	M3.1	136 km	5 km
Jun 29, 2024	22 km ESE of Hill View Heights, Wyoming	M3.0	57 km	10 km
Jan 16, 2012	25 km E of Buffalo Gap, South Dakota	M3.0	42 km	5 km
Mar 10, 2011	22 km N of Van Tassell, Wyoming	M2.9	131 km	5 km
Jun 16, 2024	7 km NNE of Buffalo Gap, South Dakota	M2.9	33 km	8 km
Jul 17, 2016	15 km NNE of Oelrichs, South Dakota	M2.8	59 km	5 km
Mar 18, 1994	4 km SSW of Hot Springs, South Dakota	M2.8	55 km	5 km
Apr 4, 2024	19 km SW of Interior, South Dakota	M2.8	86 km	9 km
Jan 5, 2004	28 km SSE of Hill View Heights, Wyoming	M2.8	70 km	5 km
Sep 5, 1993	4 km NNW of Central City, South Dakota	M2.7	79 km	5 km

Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.

Tornado History

182 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 1 fatality, 96 injuries.

Date	Rating	Distance	Path	Fatalities
Jun 29, 1993	EF3	91 km	3.0 mi	0
May 11, 1991	EF3	40 km	2.0 mi	0
Jul 18, 1965	EF3	89 km	0.1 mi	0
Jul 12, 1965	EF3	96 km	20.8 mi	0
Aug 6, 1956	EF3	94 km	28.3 mi	0
Jul 6, 2020	EF2	88 km	2.1 mi	0
Jul 6, 2020	EF2	85 km	5.1 mi	0
Jun 13, 2016	EF2	5 km	7.4 mi	0
Jun 19, 2015	EF2	66 km	19.7 mi	0
Jun 22, 2012	EF2	97 km	16.7 mi	0
Jun 4, 1999	EF2	92 km	15.0 mi	1
Jun 4, 1999	EF2	82 km	4.0 mi	0
Jun 7, 1994	EF2	67 km	10.0 mi	0
Jul 12, 1993	EF2	69 km	2.0 mi	0
May 11, 1991	EF2	38 km	1.0 mi	0
Aug 17, 1983	EF2	72 km	0.2 mi	0
Jun 19, 1983	EF2	75 km	22.0 mi	0
Jun 5, 1982	EF2	98 km	7.0 mi	0
Jun 28, 1972	EF2	90 km	0.1 mi	0
Jul 23, 1969	EF2	64 km	0.2 mi	0

Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).

Wildfire History

20 wildfires (100+ acres) recorded within 100 km. Largest: JASPER (82,298 acres, 2000).

Year	Name	Acres Burned	Distance
2000	JASPER	82,298	55 km
2012	OIL CREEK	63,182	91 km
2017	LEGION LAKE	54,868	25 km
2007	STAMPEDE	22,848	95 km
1985	FLINT HILLS	21,062	66 km
2016	FREEMAN	19,121	57 km
1985	4TH OFJULY	18,177	94 km
2003	RED POINT	18,057	73 km
2012	HAY CANYON	17,815	62 km
1988	GALENA	16,936	18 km
2002	BATTLE CREEK	15,034	16 km
1990	SWEDLUND	14,673	31 km
2016	INDIAN CANYON	13,791	82 km
2001	ELK MOUNTAIN 2	13,758	72 km
2001	ROGERS SHACK	11,794	57 km
2022	CASINO	11,583	82 km
2002	GRIZZLY GULCH	11,487	70 km
1987	GRASS CK3	11,125	79 km
2001	WEST HELL CANYON	11,097	65 km
2007	ALABAUGH	10,650	61 km

Source: NIFC/IRWIN Wildfire Records (100+ acres).

Monthly Weather

Month	Avg Temperature	Precipitation	Summary
January	28°F (-2°C)	0.3 in	Driest
February	28°F (-2°C)	0.4 in
March	35°F (2°C)	0.9 in
April	44°F (7°C)	2.0 in
May	54°F (12°C)	3.2 in	Wettest
June	64°F (18°C)	3.2 in
July	69°F (21°C)	2.6 in
August	70°F (21°C)	1.7 in	Warmest
September	60°F (15°C)	1.3 in
October	48°F (9°C)	1.2 in
November	34°F (1°C)	0.5 in
December	27°F (-3°C)	0.4 in	Coldest

Hermosa has a seasonal temperature swing of 43°F / from 27°F in December to 70°F in August. Total annual precipitation is 17.6 inches, with May being the wettest month (3.2") and January the driest (0.3").

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