Casey weather by month
What a typical year looks like in Casey, Illinois: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Casey, 1 km from Casey; records cover 1893–2026.
The year at a glance
- Precipitation a year
- 45.5 in1157 mm
- Snow a year
- 12 in30 cm
- Last spring freeze
- Apr 15
- First fall freeze
- Oct 18
- Heating degree days
- 5,172
- Cooling degree days
- 1,228
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
Casey in January
Highs average 38°3° and lows 19°−7°, with 3.3 in83 mm of precipitation and 5 in13 cm of snow in a typical January.
- Record high
- 72°22° (1909)
- Record low
- −22°−30° (1904)
- Heating degree days
- 1134
- Cooling degree days
- 0
Casey in February
Highs average 43°6° and lows 22°−5°, with 2.6 in66 mm of precipitation and 1.9 in4.8 cm of snow in a typical February.
- Record high
- 76°24° (2016)
- Record low
- −22°−30° (1905)
- Heating degree days
- 914
- Cooling degree days
- 0
Casey in March
Highs average 53°12° and lows 32°0°, with 3.3 in85 mm of precipitation and 1.4 in3.6 cm of snow in a typical March.
- Record high
- 88°31° (2026)
- Record low
- −4°−20° (1899)
- Heating degree days
- 694
- Cooling degree days
- 0
Casey in April
Highs average 65°18° and lows 43°6°, with 5.1 in129 mm of precipitation and 0.1 in0.3 cm of snow in a typical April.
- Record high
- 89°32° (1906)
- Record low
- 18°−8° (1982)
- Heating degree days
- 341
- Cooling degree days
- 11
Casey in May
Highs average 76°24° and lows 54°12°, with 4.5 in114 mm of precipitation in a typical May.
- Record high
- 97°36° (1902)
- Record low
- 28°−2° (1895)
- Heating degree days
- 106
- Cooling degree days
- 103
Casey in June
Highs average 84°29° and lows 63°17°, with 5.2 in131 mm of precipitation in a typical June.
- Record high
- 100°38° (1910)
- Record low
- 35°2° (1894)
- Heating degree days
- 5
- Cooling degree days
- 255
Casey in July
Highs average 88°31° and lows 66°19°, with 4.6 in118 mm of precipitation in a typical July.
- Record high
- 102°39° (1983)
- Record low
- 46°8° (1904)
- Heating degree days
- 0
- Cooling degree days
- 363
Casey in August
Highs average 86°30° and lows 64°18°, with 3 in77 mm of precipitation in a typical August.
- Record high
- 102°39° (1983)
- Record low
- 44°7° (1893)
- Heating degree days
- 1
- Cooling degree days
- 316
Casey in September
Highs average 81°27° and lows 55°13°, with 3.1 in78 mm of precipitation in a typical September.
- Record high
- 103°39° (2026)
- Record low
- 25°−4° (1899)
- Heating degree days
- 53
- Cooling degree days
- 145
Casey in OctoberThis month
Highs average 69°20° and lows 44°7°, with 3.8 in97 mm of precipitation in a typical October.
- Record high
- 95°35° (2019)
- Record low
- 17°−8° (1895)
- Heating degree days
- 298
- Cooling degree days
- 32
Casey in November
Highs average 54°12° and lows 33°1°, with 4 in102 mm of precipitation and 0.3 in0.8 cm of snow in a typical November.
- Record high
- 83°28° (2016)
- Record low
- 3°−16° (2019)
- Heating degree days
- 640
- Cooling degree days
- 3
Casey in December
Highs average 42°6° and lows 24°−4°, with 3.1 in78 mm of precipitation and 3 in8 cm of snow in a typical December.
- Record high
- 72°22° (1982)
- Record low
- −21°−29° (1989)
- Heating degree days
- 986
- Cooling degree days
- 0