Millbrook weather by month
What a typical year looks like in Millbrook, Illinois: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Chicago Aurora Municipal Airport, 19 km from Millbrook; records cover 1998–2026.
The year at a glance
- Precipitation a year
- 33.8 in860 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 29
- First fall freeze
- Oct 11
- Heating degree days
- 6,433
- Cooling degree days
- 779
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −10°−24° (heating, 99%) and 93°34° (cooling, 1%).
Month by month
Millbrook in January
Highs average 31°−1° and lows 15°−10°, with 1.3 in33 mm of precipitation in a typical January.
- Record high
- 64°18° (2008)
- Record low
- −33°−36° (2009)
- Heating degree days
- 1314
- Cooling degree days
- 0
Millbrook in February
Highs average 35°2° and lows 18°−8°, with 1.4 in36 mm of precipitation in a typical February.
- Record high
- 74°23° (2024)
- Record low
- −23°−31° (2014)
- Heating degree days
- 1079
- Cooling degree days
- 0
Millbrook in March
Highs average 48°9° and lows 28°−2°, with 2.2 in56 mm of precipitation in a typical March.
- Record high
- 83°28° (2012)
- Record low
- −12°−24° (2002)
- Heating degree days
- 844
- Cooling degree days
- 1
Millbrook in April
Highs average 60°16° and lows 37°3°, with 3.6 in91 mm of precipitation in a typical April.
- Record high
- 90°32° (2002)
- Record low
- 14°−10° (2018)
- Heating degree days
- 491
- Cooling degree days
- 5
Millbrook in May
Highs average 72°22° and lows 49°9°, with 4.1 in103 mm of precipitation in a typical May.
- Record high
- 97°36° (2012)
- Record low
- 21°−6° (2005)
- Heating degree days
- 197
- Cooling degree days
- 56
Millbrook in June
Highs average 81°27° and lows 59°15°, with 4 in101 mm of precipitation in a typical June.
- Record high
- 98°37° (2012)
- Record low
- 35°2° (2003)
- Heating degree days
- 29
- Cooling degree days
- 177
Millbrook in July
Highs average 84°29° and lows 62°17°, with 3.7 in94 mm of precipitation in a typical July.
- Record high
- 102°39° (2012)
- Record low
- 44°7° (2001)
- Heating degree days
- 6
- Cooling degree days
- 256
Millbrook in August
Highs average 82°28° and lows 60°15°, with 3.4 in85 mm of precipitation in a typical August.
- Record high
- 97°36° (2006)
- Record low
- 40°4° (2009)
- Heating degree days
- 12
- Cooling degree days
- 193
Millbrook in September
Highs average 76°25° and lows 52°11°, with 3 in76 mm of precipitation in a typical September.
- Record high
- 95°35° (2005)
- Record low
- 29°−2° (2012)
- Heating degree days
- 113
- Cooling degree days
- 80
Millbrook in OctoberThis month
Highs average 63°17° and lows 41°5°, with 3.2 in82 mm of precipitation in a typical October.
- Record high
- 91°33° (2025)
- Record low
- 19°−7° (2003)
- Heating degree days
- 416
- Cooling degree days
- 11
Millbrook in November
Highs average 48°9° and lows 29°−2°, with 2.3 in58 mm of precipitation in a typical November.
- Record high
- 77°25° (2016)
- Record low
- 0°−18° (2015)
- Heating degree days
- 791
- Cooling degree days
- 0
Millbrook in December
Highs average 36°2° and lows 21°−6°, with 1.7 in43 mm of precipitation in a typical December.
- Record high
- 70°21° (2012)
- Record low
- −18°−28° (2016)
- Heating degree days
- 1141
- Cooling degree days
- 0