Hermosa weather by month
What a typical year looks like in Hermosa, South Dakota: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Mount Rushmore National Memorial, 22 km from Hermosa; records cover 1962–2026.
The year at a glance
- Precipitation a year
- 24.1 in613 mm
- Snow a year
- 59 in151 cm
- Last spring freeze
- May 18
- First fall freeze
- Oct 1
- Heating degree days
- 7,406
- Cooling degree days
- 416
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −7°−22° (heating, 99%) and 91°33° (cooling, 1%).
Month by month
Hermosa in January
Highs average 37°3° and lows 19°−7°, with 0.48 in12 mm of precipitation and 7 in18 cm of snow in a typical January.
- Record high
- 70°21° (2015)
- Record low
- −38°−39° (1963)
- Heating degree days
- 1153
- Cooling degree days
- 0
Hermosa in February
Highs average 36°2° and lows 18°−8°, with 0.76 in19 mm of precipitation and 9 in23 cm of snow in a typical February.
- Record high
- 68°20° (1982)
- Record low
- −29°−34° (1989)
- Heating degree days
- 1054
- Cooling degree days
- 0
Hermosa in March
Highs average 44°7° and lows 25°−4°, with 1.4 in34 mm of precipitation and 10 in24 cm of snow in a typical March.
- Record high
- 80°27° (2026)
- Record low
- −16°−27° (2014)
- Heating degree days
- 936
- Cooling degree days
- 0
Hermosa in April
Highs average 50°10° and lows 32°0°, with 2.6 in67 mm of precipitation and 13 in33 cm of snow in a typical April.
- Record high
- 85°29° (1989)
- Record low
- −3°−19° (2023)
- Heating degree days
- 720
- Cooling degree days
- 1
Hermosa in May
Highs average 60°15° and lows 42°5°, with 4.8 in122 mm of precipitation and 1.5 in3.8 cm of snow in a typical May.
- Record high
- 93°34° (1969)
- Record low
- 14°−10° (1967)
- Heating degree days
- 455
- Cooling degree days
- 7
Hermosa in June
Highs average 71°22° and lows 52°11°, with 3.6 in91 mm of precipitation and 0.2 in0.5 cm of snow in a typical June.
- Record high
- 99°37° (1970)
- Record low
- 27°−3° (1981)
- Heating degree days
- 158
- Cooling degree days
- 53
Hermosa in July
Highs average 79°26° and lows 59°15°, with 3.6 in91 mm of precipitation in a typical July.
- Record high
- 100°38° (1974)
- Record low
- 40°4° (1972)
- Heating degree days
- 39
- Cooling degree days
- 160
Hermosa in August
Highs average 78°25° and lows 58°14°, with 2.3 in58 mm of precipitation in a typical August.
- Record high
- 99°37° (1973)
- Record low
- 33°1° (1968)
- Heating degree days
- 53
- Cooling degree days
- 138
Hermosa in September
Highs average 69°21° and lows 50°10°, with 1.8 in45 mm of precipitation and 0.9 in2.3 cm of snow in a typical September.
- Record high
- 97°36° (1978)
- Record low
- 19°−7° (1984)
- Heating degree days
- 223
- Cooling degree days
- 54
Hermosa in OctoberThis month
Highs average 55°13° and lows 37°3°, with 1.8 in46 mm of precipitation and 5 in12 cm of snow in a typical October.
- Record high
- 86°30° (2011)
- Record low
- −4°−20° (2020)
- Heating degree days
- 595
- Cooling degree days
- 3
Hermosa in November
Highs average 44°7° and lows 27°−3°, with 0.59 in15 mm of precipitation and 6 in16 cm of snow in a typical November.
- Record high
- 75°24° (1975)
- Record low
- −12°−24° (1985)
- Heating degree days
- 879
- Cooling degree days
- 0
Hermosa in December
Highs average 37°3° and lows 20°−7°, with 0.5 in13 mm of precipitation and 7 in17 cm of snow in a typical December.
- Record high
- 68°20° (2014)
- Record low
- −31°−35° (1983)
- Heating degree days
- 1141
- Cooling degree days
- 0