Heritage Lake weather by month
What a typical year looks like in Heritage Lake, Illinois: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Congerville 2nw, 11 km from Heritage Lake; records cover 1996–2026.
The year at a glance
- Precipitation a year
- 37.5 in952 mm
- Snow a year
- 22 in57 cm
- Last spring freeze
- Apr 28
- First fall freeze
- Oct 12
- Heating degree days
- 5,753
- Cooling degree days
- 1,067
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −6°−21° (heating, 99%) and 95°35° (cooling, 1%).
Month by month
Heritage Lake in January
Highs average 33°1° and lows 17°−8°, with 2.1 in52 mm of precipitation and 7 in17 cm of snow in a typical January.
- Record high
- 66°19° (2008)
- Record low
- −36°−38° (1999)
- Heating degree days
- 1235
- Cooling degree days
- 0
Heritage Lake in February
Highs average 38°3° and lows 21°−6°, with 1.8 in45 mm of precipitation and 5 in13 cm of snow in a typical February.
- Record high
- 77°25° (2024)
- Record low
- −23°−31° (2014)
- Heating degree days
- 998
- Cooling degree days
- 0
Heritage Lake in March
Highs average 50°10° and lows 31°−1°, with 2.4 in62 mm of precipitation and 2.8 in7.1 cm of snow in a typical March.
- Record high
- 87°31° (2026)
- Record low
- −6°−21° (2014)
- Heating degree days
- 756
- Cooling degree days
- 3
Heritage Lake in April
Highs average 63°17° and lows 41°5°, with 3.8 in96 mm of precipitation and 0.8 in2 cm of snow in a typical April.
- Record high
- 90°32° (2002)
- Record low
- 7°−14° (2018)
- Heating degree days
- 405
- Cooling degree days
- 13
Heritage Lake in May
Highs average 74°23° and lows 52°11°, with 4.8 in121 mm of precipitation in a typical May.
- Record high
- 96°36° (2018)
- Record low
- 23°−5° (2005)
- Heating degree days
- 156
- Cooling degree days
- 86
Heritage Lake in June
Highs average 83°28° and lows 61°16°, with 4.1 in103 mm of precipitation in a typical June.
- Record high
- 99°37° (2012)
- Record low
- 35°2° (2003)
- Heating degree days
- 20
- Cooling degree days
- 226
Heritage Lake in July
Highs average 86°30° and lows 65°18°, with 3.9 in98 mm of precipitation in a typical July.
- Record high
- 104°40° (2012)
- Record low
- 46°8° (1997)
- Heating degree days
- 2
- Cooling degree days
- 317
Heritage Lake in August
Highs average 84°29° and lows 63°17°, with 3.7 in95 mm of precipitation in a typical August.
- Record high
- 100°38° (2023)
- Record low
- 40°4° (2004)
- Heating degree days
- 5
- Cooling degree days
- 265
Heritage Lake in September
Highs average 80°27° and lows 55°13°, with 3.2 in82 mm of precipitation in a typical September.
- Record high
- 100°38° (2011)
- Record low
- 30°−1° (2012)
- Heating degree days
- 70
- Cooling degree days
- 132
Heritage Lake in OctoberThis month
Highs average 67°19° and lows 43°6°, with 3.1 in80 mm of precipitation in a typical October.
- Record high
- 93°34° (2006)
- Record low
- 20°−7° (1999)
- Heating degree days
- 345
- Cooling degree days
- 24
Heritage Lake in November
Highs average 51°11° and lows 32°0°, with 2.6 in67 mm of precipitation and 1.5 in3.8 cm of snow in a typical November.
- Record high
- 82°28° (2000)
- Record low
- 5°−15° (2019)
- Heating degree days
- 698
- Cooling degree days
- 1
Heritage Lake in December
Highs average 39°4° and lows 23°−5°, with 2 in52 mm of precipitation and 5 in13 cm of snow in a typical December.
- Record high
- 72°22° (1998)
- Record low
- −18°−28° (2000)
- Heating degree days
- 1063
- Cooling degree days
- 0