Mattoon weather by month
What a typical year looks like in Mattoon, Illinois: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at CHARLESTON, 17 km from Mattoon; records cover 1896–2026.
The year at a glance
- Precipitation a year
- 43.8 in1111 mm
- Snow a year
- 19 in48 cm
- Last spring freeze
- Apr 16
- First fall freeze
- Oct 14
- Heating degree days
- 4,928
- Cooling degree days
- 1,336
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 1°−17° (heating, 99%) and 96°36° (cooling, 1%).
Month by month
Mattoon in January
Highs average 38°3° and lows 21°−6°, with 2.5 in65 mm of precipitation and 8 in21 cm of snow in a typical January.
- Record high
- 71°22° (1909)
- Record low
- −27°−33° (1994)
- Heating degree days
- 1106
- Cooling degree days
- 0
Mattoon in February
Highs average 43°6° and lows 25°−4°, with 2.7 in68 mm of precipitation and 6 in14 cm of snow in a typical February.
- Record high
- 77°25° (2024)
- Record low
- −23°−31° (1905)
- Heating degree days
- 869
- Cooling degree days
- 0
Mattoon in March
Highs average 54°12° and lows 34°1°, with 3.1 in79 mm of precipitation and 1.3 in3.3 cm of snow in a typical March.
- Record high
- 89°32° (1929)
- Record low
- −14°−26° (1960)
- Heating degree days
- 657
- Cooling degree days
- 4
Mattoon in April
Highs average 67°20° and lows 44°7°, with 5.1 in129 mm of precipitation and 0.3 in0.8 cm of snow in a typical April.
- Record high
- 92°33° (1930)
- Record low
- 14°−10° (2018)
- Heating degree days
- 302
- Cooling degree days
- 23
Mattoon in May
Highs average 77°25° and lows 54°12°, with 4.5 in115 mm of precipitation in a typical May.
- Record high
- 101°38° (1934)
- Record low
- 26°−3° (1925)
- Heating degree days
- 97
- Cooling degree days
- 116
Mattoon in June
Highs average 86°30° and lows 63°17°, with 4.8 in123 mm of precipitation in a typical June.
- Record high
- 108°42° (1934)
- Record low
- 35°2° (1945)
- Heating degree days
- 9
- Cooling degree days
- 286
Mattoon in July
Highs average 88°31° and lows 66°19°, with 4.4 in112 mm of precipitation in a typical July.
- Record high
- 110°43° (1936)
- Record low
- 45°7° (1937)
- Heating degree days
- 0
- Cooling degree days
- 377
Mattoon in August
Highs average 87°30° and lows 64°18°, with 2.9 in75 mm of precipitation in a typical August.
- Record high
- 107°42° (1918)
- Record low
- 39°4° (1915)
- Heating degree days
- 2
- Cooling degree days
- 327
Mattoon in September
Highs average 81°27° and lows 57°14°, with 3.2 in80 mm of precipitation in a typical September.
- Record high
- 104°40° (1925)
- Record low
- 25°−4° (1899)
- Heating degree days
- 47
- Cooling degree days
- 167
Mattoon in OctoberThis month
Highs average 69°21° and lows 46°8°, with 3.9 in100 mm of precipitation in a typical October.
- Record high
- 94°34° (1922)
- Record low
- 11°−12° (1925)
- Heating degree days
- 274
- Cooling degree days
- 34
Mattoon in November
Highs average 54°12° and lows 35°2°, with 3.7 in95 mm of precipitation and 0.8 in2 cm of snow in a typical November.
- Record high
- 84°29° (1933)
- Record low
- −2°−19° (1929)
- Heating degree days
- 612
- Cooling degree days
- 2
Mattoon in December
Highs average 42°6° and lows 26°−3°, with 2.8 in71 mm of precipitation and 3 in8 cm of snow in a typical December.
- Record high
- 73°23° (1948)
- Record low
- −20°−29° (1924)
- Heating degree days
- 953
- Cooling degree days
- 0