Rockport weather by month
What a typical year looks like in Rockport, Illinois: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Saverton Lock And Dam 22, 23 km from Rockport; records cover 1948–2026.
The year at a glance
- Precipitation a year
- 38.5 in977 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 3
- First fall freeze
- Oct 31
- Heating degree days
- 5,024
- Cooling degree days
- 1,432
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 98°37° (cooling, 1%).
Month by month
Rockport in January
Highs average 37°3° and lows 21°−6°, with 1.9 in48 mm of precipitation in a typical January.
- Record high
- 74°23° (1950)
- Record low
- −22°−30° (1977)
- Heating degree days
- 1123
- Cooling degree days
- 0
Rockport in February
Highs average 42°6° and lows 24°−5°, with 2 in52 mm of precipitation in a typical February.
- Record high
- 82°28° (1972)
- Record low
- −19°−28° (1979)
- Heating degree days
- 894
- Cooling degree days
- 0
Rockport in March
Highs average 53°12° and lows 33°1°, with 2.7 in69 mm of precipitation in a typical March.
- Record high
- 92°33° (2026)
- Record low
- −11°−24° (1980)
- Heating degree days
- 685
- Cooling degree days
- 3
Rockport in April
Highs average 65°18° and lows 44°7°, with 3.9 in99 mm of precipitation in a typical April.
- Record high
- 94°34° (2001)
- Record low
- 20°−7° (2018)
- Heating degree days
- 331
- Cooling degree days
- 18
Rockport in May
Highs average 75°24° and lows 55°13°, with 4.7 in119 mm of precipitation in a typical May.
- Record high
- 96°36° (1978)
- Record low
- 32°0° (1966)
- Heating degree days
- 101
- Cooling degree days
- 107
Rockport in June
Highs average 85°29° and lows 65°18°, with 4.4 in112 mm of precipitation in a typical June.
- Record high
- 107°42° (2012)
- Record low
- 45°7° (1966)
- Heating degree days
- 8
- Cooling degree days
- 296
Rockport in July
Highs average 89°31° and lows 69°20°, with 4.1 in103 mm of precipitation in a typical July.
- Record high
- 110°43° (1954)
- Record low
- 43°6° (1967)
- Heating degree days
- 0
- Cooling degree days
- 422
Rockport in August
Highs average 87°31° and lows 67°19°, with 3.5 in89 mm of precipitation in a typical August.
- Record high
- 112°44° (2007)
- Record low
- 47°8° (1950)
- Heating degree days
- 1
- Cooling degree days
- 377
Rockport in September
Highs average 80°27° and lows 59°15°, with 3.8 in96 mm of precipitation in a typical September.
- Record high
- 104°40° (2011)
- Record low
- 35°2° (1949)
- Heating degree days
- 45
- Cooling degree days
- 174
Rockport in OctoberThis month
Highs average 68°20° and lows 47°8°, with 2.9 in74 mm of precipitation in a typical October.
- Record high
- 95°35° (2019)
- Record low
- 22°−6° (1960)
- Heating degree days
- 264
- Cooling degree days
- 33
Rockport in November
Highs average 54°12° and lows 36°2°, with 2.6 in66 mm of precipitation in a typical November.
- Record high
- 83°28° (1950)
- Record low
- −2°−19° (1964)
- Heating degree days
- 604
- Cooling degree days
- 2
Rockport in December
Highs average 42°5° and lows 26°−3°, with 2.1 in52 mm of precipitation in a typical December.
- Record high
- 75°24° (2012)
- Record low
- −18°−28° (1989)
- Heating degree days
- 968
- Cooling degree days
- 0