Mount Vernon weather by month
What a typical year looks like in Mount Vernon, South Dakota: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Mitchell Airport, 19 km from Mount Vernon; records cover 1893–2026.
The year at a glance
- Precipitation a year
- 21.1 in537 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 30
- First fall freeze
- Oct 3
- Heating degree days
- 7,159
- Cooling degree days
- 879
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −13°−25° (heating, 99%) and 98°37° (cooling, 1%).
Month by month
Mount Vernon in January
Highs average 29°−2° and lows 9°−13°, with 0.4 in10 mm of precipitation in a typical January.
- Record high
- 68°20° (2012)
- Record low
- −38°−39° (1970)
- Heating degree days
- 1427
- Cooling degree days
- 0
Mount Vernon in February
Highs average 33°0° and lows 13°−10°, with 0.37 in9.4 mm of precipitation in a typical February.
- Record high
- 72°22° (2000)
- Record low
- −40° (1994)
- Heating degree days
- 1174
- Cooling degree days
- 0
Mount Vernon in March
Highs average 45°7° and lows 24°−4°, with 0.93 in24 mm of precipitation in a typical March.
- Record high
- 95°35° (1943)
- Record low
- −23°−31° (1956)
- Heating degree days
- 935
- Cooling degree days
- 1
Mount Vernon in April
Highs average 59°15° and lows 35°2°, with 2.1 in53 mm of precipitation in a typical April.
- Record high
- 97°36° (1962)
- Record low
- 1°−17° (1924)
- Heating degree days
- 546
- Cooling degree days
- 2
Mount Vernon in May
Highs average 71°22° and lows 48°9°, with 3.2 in80 mm of precipitation in a typical May.
- Record high
- 108°42° (1934)
- Record low
- 18°−8° (1967)
- Heating degree days
- 220
- Cooling degree days
- 43
Mount Vernon in June
Highs average 81°27° and lows 59°15°, with 3.5 in89 mm of precipitation in a typical June.
- Record high
- 111°44° (1936)
- Record low
- 31°−1° (1901)
- Heating degree days
- 33
- Cooling degree days
- 178
Mount Vernon in July
Highs average 87°30° and lows 64°18°, with 2.4 in60 mm of precipitation in a typical July.
- Record high
- 116°47° (1940)
- Record low
- 34°1° (1900)
- Heating degree days
- 4
- Cooling degree days
- 323
Mount Vernon in August
Highs average 84°29° and lows 61°16°, with 3.1 in80 mm of precipitation in a typical August.
- Record high
- 115°46° (1934)
- Record low
- 34°1° (1911)
- Heating degree days
- 11
- Cooling degree days
- 234
Mount Vernon in September
Highs average 77°25° and lows 51°11°, with 2.3 in59 mm of precipitation in a typical September.
- Record high
- 106°41° (1933)
- Record low
- 11°−12° (1899)
- Heating degree days
- 123
- Cooling degree days
- 90
Mount Vernon in OctoberThis month
Highs average 62°17° and lows 38°3°, with 1.8 in46 mm of precipitation in a typical October.
- Record high
- 96°36° (1922)
- Record low
- −8°−22° (1925)
- Heating degree days
- 481
- Cooling degree days
- 8
Mount Vernon in November
Highs average 46°8° and lows 24°−4°, with 0.55 in14 mm of precipitation in a typical November.
- Record high
- 84°29° (2020)
- Record low
- −22°−30° (1959)
- Heating degree days
- 903
- Cooling degree days
- 0
Mount Vernon in December
Highs average 32°0° and lows 14°−10°, with 0.49 in12 mm of precipitation in a typical December.
- Record high
- 70°21° (1998)
- Record low
- −34°−37° (1917)
- Heating degree days
- 1302
- Cooling degree days
- 0