Eureka weather by month
What a typical year looks like in Eureka, South Dakota: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Eureka, 1 km from Eureka; records cover 1877–2026.
The year at a glance
- Precipitation a year
- 20.2 in514 mm
- Snow a year
- 44 in113 cm
- Last spring freeze
- May 11
- First fall freeze
- Sep 26
- Heating degree days
- 8,874
- Cooling degree days
- 450
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −20°−29° (heating, 99%) and 95°35° (cooling, 1%).
Month by month
Eureka in January
Highs average 21°−6° and lows 2°−17°, with 0.36 in9.1 mm of precipitation and 7 in18 cm of snow in a typical January.
- Record high
- 58°14° (1981)
- Record low
- −44°−42° (1916)
- Heating degree days
- 1669
- Cooling degree days
- 0
Eureka in February
Highs average 25°−4° and lows 6°−15°, with 0.52 in13 mm of precipitation and 8 in19 cm of snow in a typical February.
- Record high
- 67°19° (1958)
- Record low
- −44°−42° (1917)
- Heating degree days
- 1392
- Cooling degree days
- 0
Eureka in March
Highs average 38°3° and lows 18°−8°, with 0.82 in21 mm of precipitation and 9 in22 cm of snow in a typical March.
- Record high
- 85°29° (1910)
- Record low
- −29°−34° (1917)
- Heating degree days
- 1150
- Cooling degree days
- 0
Eureka in April
Highs average 54°12° and lows 30°−1°, with 1.6 in42 mm of precipitation and 5 in12 cm of snow in a typical April.
- Record high
- 96°36° (1980)
- Record low
- −8°−22° (2018)
- Heating degree days
- 692
- Cooling degree days
- 1
Eureka in May
Highs average 67°19° and lows 42°6°, with 3.2 in81 mm of precipitation in a typical May.
- Record high
- 107°42° (1934)
- Record low
- 12°−11° (1943)
- Heating degree days
- 341
- Cooling degree days
- 14
Eureka in June
Highs average 76°24° and lows 53°12°, with 3.8 in96 mm of precipitation in a typical June.
- Record high
- 107°42° (1988)
- Record low
- 29°−2° (1917)
- Heating degree days
- 90
- Cooling degree days
- 73
Eureka in July
Highs average 82°28° and lows 58°14°, with 3.1 in79 mm of precipitation in a typical July.
- Record high
- 114°46° (1934)
- Record low
- 32°0° (1917)
- Heating degree days
- 24
- Cooling degree days
- 178
Eureka in August
Highs average 81°27° and lows 56°13°, with 2.2 in57 mm of precipitation in a typical August.
- Record high
- 109°43° (1988)
- Record low
- 29°−2° (1914)
- Heating degree days
- 41
- Cooling degree days
- 144
Eureka in September
Highs average 72°22° and lows 46°8°, with 1.8 in45 mm of precipitation in a typical September.
- Record high
- 107°42° (1931)
- Record low
- 15°−9° (1974)
- Heating degree days
- 221
- Cooling degree days
- 38
Eureka in OctoberThis month
Highs average 56°13° and lows 32°0°, with 1.7 in44 mm of precipitation and 2 in5.1 cm of snow in a typical October.
- Record high
- 94°34° (1897)
- Record low
- −6°−21° (1925)
- Heating degree days
- 662
- Cooling degree days
- 2
Eureka in November
Highs average 39°4° and lows 19°−7°, with 0.54 in14 mm of precipitation and 6 in16 cm of snow in a typical November.
- Record high
- 78°26° (1965)
- Record low
- −23°−31° (1897)
- Heating degree days
- 1092
- Cooling degree days
- 0
Eureka in December
Highs average 25°−4° and lows 8°−13°, with 0.54 in14 mm of precipitation and 8 in21 cm of snow in a typical December.
- Record high
- 64°18° (2021)
- Record low
- −45°−43° (1917)
- Heating degree days
- 1500
- Cooling degree days
- 0