River Sioux weather by month
What a typical year looks like in River Sioux, Iowa: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Tekamah Municipal Airport, 12 km from River Sioux; records cover 1996–2026.
The year at a glance
- Precipitation a year
- 28.3 in718 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 24
- First fall freeze
- Oct 8
- Heating degree days
- 6,408
- Cooling degree days
- 1,014
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −9°−23° (heating, 99%) and 97°36° (cooling, 1%).
Month by month
River Sioux in January
Highs average 32°0° and lows 12°−11°, with 0.51 in13 mm of precipitation in a typical January.
- Record high
- 69°21° (2012)
- Record low
- −25°−32° (2018)
- Heating degree days
- 1336
- Cooling degree days
- 0
River Sioux in February
Highs average 36°2° and lows 16°−9°, with 0.62 in16 mm of precipitation in a typical February.
- Record high
- 81°27° (2024)
- Record low
- −26°−32° (2021)
- Heating degree days
- 1089
- Cooling degree days
- 0
River Sioux in March
Highs average 50°10° and lows 28°−2°, with 1.5 in38 mm of precipitation in a typical March.
- Record high
- 98°37° (2026)
- Record low
- −14°−26° (1998)
- Heating degree days
- 812
- Cooling degree days
- 1
River Sioux in April
Highs average 63°17° and lows 38°3°, with 3.1 in80 mm of precipitation in a typical April.
- Record high
- 95°35° (2002)
- Record low
- 12°−11° (2018)
- Heating degree days
- 438
- Cooling degree days
- 9
River Sioux in May
Highs average 74°23° and lows 51°10°, with 4 in100 mm of precipitation in a typical May.
- Record high
- 108°42° (2013)
- Record low
- 25°−4° (1997)
- Heating degree days
- 157
- Cooling degree days
- 76
River Sioux in June
Highs average 84°29° and lows 61°16°, with 4.6 in118 mm of precipitation in a typical June.
- Record high
- 104°40° (2021)
- Record low
- 42°6° (2012)
- Heating degree days
- 16
- Cooling degree days
- 235
River Sioux in July
Highs average 87°30° and lows 65°18°, with 3.1 in77 mm of precipitation in a typical July.
- Record high
- 103°39° (2002)
- Record low
- 44°7° (2013)
- Heating degree days
- 3
- Cooling degree days
- 333
River Sioux in August
Highs average 84°29° and lows 62°16°, with 3.5 in88 mm of precipitation in a typical August.
- Record high
- 101°38° (2000)
- Record low
- 42°6° (2004)
- Heating degree days
- 8
- Cooling degree days
- 246
River Sioux in September
Highs average 78°26° and lows 52°11°, with 3.2 in82 mm of precipitation in a typical September.
- Record high
- 106°41° (2000)
- Record low
- 28°−2° (2003)
- Heating degree days
- 100
- Cooling degree days
- 100
River Sioux in OctoberThis month
Highs average 65°18° and lows 39°4°, with 2 in51 mm of precipitation in a typical October.
- Record high
- 96°36° (2015)
- Record low
- 12°−11° (2022)
- Heating degree days
- 421
- Cooling degree days
- 14
River Sioux in November
Highs average 49°9° and lows 27°−3°, with 1.3 in32 mm of precipitation in a typical November.
- Record high
- 83°28° (2006)
- Record low
- −5°−21° (2019)
- Heating degree days
- 822
- Cooling degree days
- 0
River Sioux in December
Highs average 35°2° and lows 17°−8°, with 0.89 in23 mm of precipitation in a typical December.
- Record high
- 74°23° (2021)
- Record low
- −20°−29° (2017)
- Heating degree days
- 1206
- Cooling degree days
- 0