Exeter weather by month
What a typical year looks like in Exeter, Illinois: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at Jacksonville 2, 23 km from Exeter; records cover 2006–2026.
The year at a glance
- Precipitation a year
- 41.4 in1051 mm
- Snow a year
- Rare
- Last spring freeze
- Apr 15
- First fall freeze
- Oct 22
- Heating degree days
- 5,549
- Cooling degree days
- 1,148
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −2°−19° (heating, 99%) and 97°36° (cooling, 1%).
Month by month
Exeter in January
Highs average 35°2° and lows 18°−8°, with 2.2 in56 mm of precipitation in a typical January.
- Record high
- 70°21° (2008)
- Record low
- −13°−25° (2019)
- Heating degree days
- 1195
- Cooling degree days
- 0
Exeter in February
Highs average 41°5° and lows 21°−6°, with 2 in51 mm of precipitation in a typical February.
- Record high
- 80°27° (2024)
- Record low
- −8°−22° (2014)
- Heating degree days
- 960
- Cooling degree days
- 0
Exeter in March
Highs average 52°11° and lows 30°−1°, with 3 in77 mm of precipitation in a typical March.
- Record high
- 84°29° (2012)
- Record low
- −4°−20° (2014)
- Heating degree days
- 741
- Cooling degree days
- 3
Exeter in April
Highs average 65°18° and lows 41°5°, with 4.5 in113 mm of precipitation in a typical April.
- Record high
- 92°33° (2006)
- Record low
- 16°−9° (2018)
- Heating degree days
- 380
- Cooling degree days
- 12
Exeter in May
Highs average 75°24° and lows 53°11°, with 5.1 in129 mm of precipitation in a typical May.
- Record high
- 96°36° (2018)
- Record low
- 32°0° (2011)
- Heating degree days
- 128
- Cooling degree days
- 91
Exeter in June
Highs average 83°29° and lows 62°17°, with 5 in126 mm of precipitation in a typical June.
- Record high
- 104°40° (2012)
- Record low
- 47°8° (2012)
- Heating degree days
- 8
- Cooling degree days
- 238
Exeter in July
Highs average 87°31° and lows 65°19°, with 4 in101 mm of precipitation in a typical July.
- Record high
- 104°40° (2012)
- Record low
- 51°11° (2006)
- Heating degree days
- 2
- Cooling degree days
- 348
Exeter in August
Highs average 86°30° and lows 63°17°, with 3.3 in84 mm of precipitation in a typical August.
- Record high
- 104°40° (2007)
- Record low
- 48°9° (2025)
- Heating degree days
- 3
- Cooling degree days
- 296
Exeter in September
Highs average 80°27° and lows 55°13°, with 3.8 in96 mm of precipitation in a typical September.
- Record high
- 102°39° (2011)
- Record low
- 38°3° (2012)
- Heating degree days
- 66
- Cooling degree days
- 135
Exeter in OctoberThis month
Highs average 67°19° and lows 43°6°, with 3.1 in79 mm of precipitation in a typical October.
- Record high
- 94°34° (2006)
- Record low
- 23°−5° (2017)
- Heating degree days
- 336
- Cooling degree days
- 24
Exeter in November
Highs average 52°11° and lows 32°0°, with 3.1 in78 mm of precipitation in a typical November.
- Record high
- 82°28° (2016)
- Record low
- 0°−18° (1948)
- Heating degree days
- 689
- Cooling degree days
- 1
Exeter in December
Highs average 40°4° and lows 23°−5°, with 2.4 in60 mm of precipitation in a typical December.
- Record high
- 72°22° (2012)
- Record low
- −10°−23° (2022)
- Heating degree days
- 1041
- Cooling degree days
- 0