Swea City weather by month
What a typical year looks like in Swea City, Iowa: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Swea City 5n, 8 km from Swea City; records cover 1954–2026.
The year at a glance
- Precipitation a year
- 32.9 in835 mm
- Snow a year
- 40 in101 cm
- Last spring freeze
- Apr 29
- First fall freeze
- Oct 2
- Heating degree days
- 8,173
- Cooling degree days
- 497
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −15°−26° (heating, 99%) and 93°34° (cooling, 1%).
Month by month
Swea City in January
Highs average 22°−6° and lows 5°−15°, with 0.87 in22 mm of precipitation and 11 in28 cm of snow in a typical January.
- Record high
- 58°14° (2003)
- Record low
- −32°−36° (1970)
- Heating degree days
- 1606
- Cooling degree days
- 0
Swea City in February
Highs average 27°−3° and lows 8°−13°, with 0.93 in24 mm of precipitation and 9 in22 cm of snow in a typical February.
- Record high
- 69°21° (2024)
- Record low
- −28°−33° (1996)
- Heating degree days
- 1330
- Cooling degree days
- 0
Swea City in March
Highs average 40°4° and lows 21°−6°, with 1.8 in45 mm of precipitation and 5 in12 cm of snow in a typical March.
- Record high
- 86°30° (2025)
- Record low
- −20°−29° (1962)
- Heating degree days
- 1068
- Cooling degree days
- 0
Swea City in April
Highs average 55°13° and lows 33°0°, with 3.4 in87 mm of precipitation and 4 in9 cm of snow in a typical April.
- Record high
- 93°34° (1980)
- Record low
- 0°−18° (1975)
- Heating degree days
- 633
- Cooling degree days
- 2
Swea City in May
Highs average 68°20° and lows 46°8°, with 4.6 in117 mm of precipitation in a typical May.
- Record high
- 104°40° (2013)
- Record low
- 10°−12° (1967)
- Heating degree days
- 287
- Cooling degree days
- 28
Swea City in June
Highs average 78°25° and lows 57°14°, with 4.7 in118 mm of precipitation in a typical June.
- Record high
- 105°41° (1985)
- Record low
- 35°2° (1969)
- Heating degree days
- 50
- Cooling degree days
- 120
Swea City in July
Highs average 81°27° and lows 60°15°, with 4.2 in106 mm of precipitation in a typical July.
- Record high
- 104°40° (1955)
- Record low
- 43°6° (1971)
- Heating degree days
- 14
- Cooling degree days
- 178
Swea City in August
Highs average 78°26° and lows 58°14°, with 4.1 in104 mm of precipitation in a typical August.
- Record high
- 101°38° (1988)
- Record low
- 38°3° (2004)
- Heating degree days
- 34
- Cooling degree days
- 123
Swea City in September
Highs average 73°23° and lows 48°9°, with 3.2 in82 mm of precipitation in a typical September.
- Record high
- 98°37° (1984)
- Record low
- 22°−6° (1967)
- Heating degree days
- 183
- Cooling degree days
- 42
Swea City in OctoberThis month
Highs average 59°15° and lows 35°2°, with 2.5 in64 mm of precipitation and 0.7 in1.8 cm of snow in a typical October.
- Record high
- 94°34° (1963)
- Record low
- 6°−14° (2020)
- Heating degree days
- 564
- Cooling degree days
- 4
Swea City in November
Highs average 42°5° and lows 22°−5°, with 1.5 in37 mm of precipitation and 3 in8 cm of snow in a typical November.
- Record high
- 81°27° (2006)
- Record low
- −16°−27° (2014)
- Heating degree days
- 990
- Cooling degree days
- 0
Swea City in December
Highs average 28°−2° and lows 11°−12°, with 1.2 in30 mm of precipitation and 8 in21 cm of snow in a typical December.
- Record high
- 69°21° (1998)
- Record low
- −28°−33° (1983)
- Heating degree days
- 1414
- Cooling degree days
- 0