Knollwood weather by month
What a typical year looks like in Knollwood, Illinois: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Chicago Palwaukee Airport, 18 km from Knollwood; records cover 1996–2026.
The year at a glance
- Precipitation a year
- 32.3 in820 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 22
- First fall freeze
- Oct 22
- Heating degree days
- 6,086
- Cooling degree days
- 933
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −2°−19° (heating, 99%) and 94°34° (cooling, 1%).
Month by month
Knollwood in January
Highs average 32°0° and lows 18°−8°, with 1.3 in34 mm of precipitation in a typical January.
- Record high
- 65°18° (2008)
- Record low
- −21°−29° (2019)
- Heating degree days
- 1235
- Cooling degree days
- 0
Knollwood in February
Highs average 36°2° and lows 21°−6°, with 1.3 in33 mm of precipitation in a typical February.
- Record high
- 75°24° (2024)
- Record low
- −12°−24° (2015)
- Heating degree days
- 1022
- Cooling degree days
- 0
Knollwood in March
Highs average 47°8° and lows 30°−1°, with 1.8 in47 mm of precipitation in a typical March.
- Record high
- 86°30° (2012)
- Record low
- −4°−20° (2014)
- Heating degree days
- 825
- Cooling degree days
- 2
Knollwood in April
Highs average 58°15° and lows 39°4°, with 3.3 in84 mm of precipitation in a typical April.
- Record high
- 88°31° (2002)
- Record low
- 20°−7° (1997)
- Heating degree days
- 495
- Cooling degree days
- 6
Knollwood in May
Highs average 70°21° and lows 50°10°, with 3.8 in96 mm of precipitation in a typical May.
- Record high
- 97°36° (2018)
- Record low
- 29°−2° (2004)
- Heating degree days
- 220
- Cooling degree days
- 52
Knollwood in June
Highs average 80°26° and lows 60°16°, with 4 in101 mm of precipitation in a typical June.
- Record high
- 99°37° (2012)
- Record low
- 37°3° (2003)
- Heating degree days
- 37
- Cooling degree days
- 181
Knollwood in July
Highs average 84°29° and lows 66°19°, with 3.2 in80 mm of precipitation in a typical July.
- Record high
- 104°40° (2012)
- Record low
- 50°10° (1996)
- Heating degree days
- 3
- Cooling degree days
- 310
Knollwood in August
Highs average 82°28° and lows 65°18°, with 3.7 in94 mm of precipitation in a typical August.
- Record high
- 100°38° (2023)
- Record low
- 47°8° (2009)
- Heating degree days
- 4
- Cooling degree days
- 263
Knollwood in September
Highs average 75°24° and lows 56°13°, with 3 in77 mm of precipitation in a typical September.
- Record high
- 96°36° (2013)
- Record low
- 34°1° (2012)
- Heating degree days
- 82
- Cooling degree days
- 106
Knollwood in OctoberThis month
Highs average 63°17° and lows 45°7°, with 3.1 in79 mm of precipitation in a typical October.
- Record high
- 89°32° (1997)
- Record low
- 25°−4° (2023)
- Heating degree days
- 370
- Cooling degree days
- 13
Knollwood in November
Highs average 49°9° and lows 33°1°, with 2.2 in55 mm of precipitation in a typical November.
- Record high
- 76°24° (2016)
- Record low
- 9°−13° (2019)
- Heating degree days
- 722
- Cooling degree days
- 0
Knollwood in December
Highs average 37°3° and lows 24°−4°, with 1.6 in42 mm of precipitation in a typical December.
- Record high
- 69°21° (2001)
- Record low
- −8°−22° (2000)
- Heating degree days
- 1071
- Cooling degree days
- 0