Keyesport weather by month
What a typical year looks like in Keyesport, Illinois: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Carlyle Reservoir, 16 km from Keyesport; records cover 1962–2026.
The year at a glance
- Precipitation a year
- 45.9 in1165 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 10
- First fall freeze
- Oct 29
- Heating degree days
- 4,780
- Cooling degree days
- 1,438
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are 2°−17° (heating, 99%) and 96°36° (cooling, 1%).
Month by month
Keyesport in January
Highs average 39°4° and lows 22°−6°, with 3.1 in77 mm of precipitation in a typical January.
- Record high
- 73°23° (2008)
- Record low
- −22°−30° (1994)
- Heating degree days
- 1075
- Cooling degree days
- 0
Keyesport in February
Highs average 45°7° and lows 25°−4°, with 2.5 in62 mm of precipitation in a typical February.
- Record high
- 77°25° (2000)
- Record low
- −20°−29° (1982)
- Heating degree days
- 844
- Cooling degree days
- 0
Keyesport in March
Highs average 55°13° and lows 35°1°, with 3.7 in93 mm of precipitation in a typical March.
- Record high
- 89°32° (2026)
- Record low
- −5°−21° (1978)
- Heating degree days
- 634
- Cooling degree days
- 4
Keyesport in April
Highs average 67°19° and lows 45°7°, with 4.9 in124 mm of precipitation in a typical April.
- Record high
- 89°32° (1987)
- Record low
- 22°−6° (1972)
- Heating degree days
- 302
- Cooling degree days
- 22
Keyesport in May
Highs average 76°24° and lows 56°13°, with 5.2 in133 mm of precipitation in a typical May.
- Record high
- 97°36° (1967)
- Record low
- 31°−1° (1966)
- Heating degree days
- 90
- Cooling degree days
- 117
Keyesport in June
Highs average 85°29° and lows 65°18°, with 4.9 in124 mm of precipitation in a typical June.
- Record high
- 104°40° (2012)
- Record low
- 41°5° (1963)
- Heating degree days
- 7
- Cooling degree days
- 302
Keyesport in July
Highs average 88°31° and lows 68°20°, with 4.2 in108 mm of precipitation in a typical July.
- Record high
- 105°41° (2012)
- Record low
- 50°10° (1985)
- Heating degree days
- 0
- Cooling degree days
- 409
Keyesport in August
Highs average 87°31° and lows 66°19°, with 3.6 in91 mm of precipitation in a typical August.
- Record high
- 104°40° (1962)
- Record low
- 43°6° (1965)
- Heating degree days
- 1
- Cooling degree days
- 367
Keyesport in September
Highs average 81°27° and lows 58°15°, with 3.7 in93 mm of precipitation in a typical September.
- Record high
- 101°38° (2026)
- Record low
- 35°2° (1983)
- Heating degree days
- 40
- Cooling degree days
- 177
Keyesport in OctoberThis month
Highs average 70°21° and lows 46°8°, with 3.4 in86 mm of precipitation in a typical October.
- Record high
- 95°35° (2019)
- Record low
- 21°−6° (1981)
- Heating degree days
- 258
- Cooling degree days
- 38
Keyesport in November
Highs average 55°13° and lows 36°2°, with 3.7 in94 mm of precipitation in a typical November.
- Record high
- 83°28° (1968)
- Record low
- 0°−18° (1964)
- Heating degree days
- 593
- Cooling degree days
- 2
Keyesport in December
Highs average 43°6° and lows 26°−3°, with 3.1 in79 mm of precipitation in a typical December.
- Record high
- 74°23° (1970)
- Record low
- −19°−28° (1989)
- Heating degree days
- 936
- Cooling degree days
- 0