Sun Valley Lake weather by month
What a typical year looks like in Sun Valley Lake, Iowa: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Mount Ayr, 22 km from Sun Valley Lake; records cover 1893–2026.
The year at a glance
- Precipitation a year
- 37 in939 mm
- Snow a year
- 21 in52 cm
- Last spring freeze
- Apr 24
- First fall freeze
- Oct 10
- Heating degree days
- 6,422
- Cooling degree days
- 867
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −8°−22° (heating, 99%) and 94°34° (cooling, 1%).
Month by month
Sun Valley Lake in January
Highs average 32°0° and lows 12°−11°, with 0.73 in19 mm of precipitation and 6 in15 cm of snow in a typical January.
- Record high
- 67°19° (1989)
- Record low
- −30°−34° (1912)
- Heating degree days
- 1339
- Cooling degree days
- 0
Sun Valley Lake in February
Highs average 37°3° and lows 16°−9°, with 1.3 in32 mm of precipitation and 6 in15 cm of snow in a typical February.
- Record high
- 80°27° (1930)
- Record low
- −29°−34° (1996)
- Heating degree days
- 1079
- Cooling degree days
- 0
Sun Valley Lake in March
Highs average 49°10° and lows 28°−2°, with 2.2 in55 mm of precipitation and 2.6 in6.6 cm of snow in a typical March.
- Record high
- 92°33° (2026)
- Record low
- −20°−29° (1960)
- Heating degree days
- 824
- Cooling degree days
- 1
Sun Valley Lake in April
Highs average 61°16° and lows 38°3°, with 3.4 in86 mm of precipitation and 0.7 in1.8 cm of snow in a typical April.
- Record high
- 92°33° (1910)
- Record low
- 5°−15° (1920)
- Heating degree days
- 464
- Cooling degree days
- 5
Sun Valley Lake in May
Highs average 71°22° and lows 50°10°, with 5.4 in136 mm of precipitation in a typical May.
- Record high
- 103°39° (1934)
- Record low
- 22°−6° (1903)
- Heating degree days
- 193
- Cooling degree days
- 46
Sun Valley Lake in June
Highs average 80°27° and lows 60°15°, with 5.4 in137 mm of precipitation in a typical June.
- Record high
- 105°41° (1933)
- Record low
- 36°2° (1969)
- Heating degree days
- 26
- Cooling degree days
- 175
Sun Valley Lake in July
Highs average 85°29° and lows 64°18°, with 4.4 in112 mm of precipitation in a typical July.
- Record high
- 112°44° (1936)
- Record low
- 41°5° (1982)
- Heating degree days
- 4
- Cooling degree days
- 291
Sun Valley Lake in August
Highs average 83°29° and lows 62°17°, with 4 in101 mm of precipitation in a typical August.
- Record high
- 111°44° (1934)
- Record low
- 37°3° (1917)
- Heating degree days
- 9
- Cooling degree days
- 243
Sun Valley Lake in September
Highs average 76°25° and lows 53°12°, with 3.7 in94 mm of precipitation in a typical September.
- Record high
- 105°41° (1913)
- Record low
- 24°−4° (1899)
- Heating degree days
- 107
- Cooling degree days
- 94
Sun Valley Lake in OctoberThis month
Highs average 64°18° and lows 40°5°, with 2.9 in73 mm of precipitation and 0.3 in0.8 cm of snow in a typical October.
- Record high
- 93°34° (1897)
- Record low
- 0°−18° (1925)
- Heating degree days
- 410
- Cooling degree days
- 12
Sun Valley Lake in November
Highs average 49°9° and lows 28°−2°, with 2.1 in54 mm of precipitation and 1.2 in3 cm of snow in a typical November.
- Record high
- 82°28° (1938)
- Record low
- −15°−26° (1964)
- Heating degree days
- 797
- Cooling degree days
- 0
Sun Valley Lake in December
Highs average 37°3° and lows 18°−8°, with 1.6 in41 mm of precipitation and 4 in10 cm of snow in a typical December.
- Record high
- 70°21° (1946)
- Record low
- −28°−33° (1989)
- Heating degree days
- 1170
- Cooling degree days
- 0