Hammond weather by month
What a typical year looks like in Hammond, Illinois: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Decatur Airport, 24 km from Hammond; records cover 2000–2026.
The year at a glance
- Precipitation a year
- 36.4 in924 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 18
- First fall freeze
- Oct 17
- Heating degree days
- 5,393
- Cooling degree days
- 1,105
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 0°−18° (heating, 99%) and 95°35° (cooling, 1%).
Month by month
Hammond in January
Highs average 35°2° and lows 20°−7°, with 2 in51 mm of precipitation in a typical January.
- Record high
- 68°20° (2008)
- Record low
- −16°−27° (2019)
- Heating degree days
- 1165
- Cooling degree days
- 0
Hammond in February
Highs average 40°4° and lows 23°−5°, with 1.8 in47 mm of precipitation in a typical February.
- Record high
- 77°25° (2024)
- Record low
- −10°−23° (2014)
- Heating degree days
- 935
- Cooling degree days
- 0
Hammond in March
Highs average 52°11° and lows 32°0°, with 2.5 in64 mm of precipitation in a typical March.
- Record high
- 88°31° (2026)
- Record low
- −9°−23° (2015)
- Heating degree days
- 711
- Cooling degree days
- 3
Hammond in April
Highs average 64°18° and lows 42°6°, with 3.7 in93 mm of precipitation in a typical April.
- Record high
- 88°31° (2007)
- Record low
- 12°−11° (2018)
- Heating degree days
- 370
- Cooling degree days
- 13
Hammond in May
Highs average 74°24° and lows 53°12°, with 4.4 in111 mm of precipitation in a typical May.
- Record high
- 97°36° (2018)
- Record low
- 29°−2° (2005)
- Heating degree days
- 128
- Cooling degree days
- 94
Hammond in June
Highs average 83°28° and lows 62°17°, with 4.4 in111 mm of precipitation in a typical June.
- Record high
- 103°39° (2012)
- Record low
- 37°3° (2003)
- Heating degree days
- 11
- Cooling degree days
- 242
Hammond in July
Highs average 86°30° and lows 66°19°, with 3.3 in84 mm of precipitation in a typical July.
- Record high
- 104°40° (2012)
- Record low
- 46°8° (2001)
- Heating degree days
- 1
- Cooling degree days
- 333
Hammond in August
Highs average 84°29° and lows 63°17°, with 3 in77 mm of precipitation in a typical August.
- Record high
- 100°38° (2007)
- Record low
- 46°8° (2004)
- Heating degree days
- 4
- Cooling degree days
- 273
Hammond in September
Highs average 79°26° and lows 55°13°, with 3 in76 mm of precipitation in a typical September.
- Record high
- 101°38° (2011)
- Record low
- 35°2° (2012)
- Heating degree days
- 66
- Cooling degree days
- 124
Hammond in OctoberThis month
Highs average 66°19° and lows 44°7°, with 3.2 in81 mm of precipitation in a typical October.
- Record high
- 93°34° (2007)
- Record low
- 23°−5° (2018)
- Heating degree days
- 325
- Cooling degree days
- 22
Hammond in November
Highs average 51°11° and lows 34°1°, with 3 in75 mm of precipitation in a typical November.
- Record high
- 80°27° (2016)
- Record low
- 5°−15° (2019)
- Heating degree days
- 668
- Cooling degree days
- 1
Hammond in December
Highs average 40°4° and lows 25°−4°, with 2.1 in54 mm of precipitation in a typical December.
- Record high
- 72°22° (2012)
- Record low
- −14°−26° (2025)
- Heating degree days
- 1009
- Cooling degree days
- 0