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Bannockburn weather by month

What a typical year looks like in Bannockburn, 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, 9 km from Bannockburn; records cover 1996–2026.

Today’s Bannockburn forecast

The year at a glance

January: typical high 31.9°F, low 18.4°F, precipitation 1.33 in. February: typical high 35.8°F, low 21.2°F, precipitation 1.28 in. March: typical high 46.7°F, low 30.2°F, precipitation 1.84 in. April: typical high 58.1°F, low 39.3°F, precipitation 3.31 in. May: typical high 69.5°F, low 49.7°F, precipitation 3.76 in. June: typical high 79.5°F, low 60.1°F, precipitation 3.97 in. July: typical high 84°F, low 65.8°F, precipitation 3.15 in. August: typical high 82°F, low 64.7°F, precipitation 3.7 in. September: typical high 75.3°F, low 56.3°F, precipitation 3.04 in. October: typical high 62.5°F, low 44.5°F, precipitation 3.11 in. November: typical high 48.5°F, low 33.4°F, precipitation 2.15 in. December: typical high 36.9°F, low 24°F, precipitation 1.64 in.−30°−34°−10°−23°10°−12°30°−1°50°10°70°21°90°32°110°43°32°0°18°−8°Jan36°2°21°−6°Feb47°8°30°−1°Mar58°15°39°4°Apr70°21°50°10°May80°26°60°16°Jun84°29°66°19°Jul82°28°65°18°Aug75°24°56°13°Sep63°17°45°7°Oct49°9°33°1°Nov37°3°24°−4°DecPrecipitation
Bars: typical low to high (official normals, 1991–2020) Record high Record low
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

Bannockburn 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

Bannockburn 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

Bannockburn 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

Bannockburn 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

Bannockburn 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

Bannockburn 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

Bannockburn 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

Bannockburn 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

Bannockburn 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

Bannockburn 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

Bannockburn 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

Bannockburn 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