Weather history and climate summary information is available for the following locations:
- Belleville
- Chicago
- Moline
- Peoria
- Springfield
Warmest January Days
The warmest January days in Illinois are:
| Belleville, Illinois | 1950 | 75°F |
| Belleville, Illinois | 1943 | 74.3°F |
| Belleville, Illinois | 1952 | 73.9°F |
| Belleville, Illinois | 1989 | 73°F |
| Belleville, Illinois | 1967 | 73°F |
Coldest January Days
The coldest January days in Illinois were:
| Moline, Illinois | 2009 | -29.2°F |
| Chicago, Illinois | 1985 | -27°F |
| Moline, Illinois | 1979 | -27°F |
| Moline, Illinois | 1999 | -26°F |
| Chicago, Illinois | 1982 | -26°F |
Wettest January Days
The wettest single days in January occurred:
| Moline, Illinois | 1973 | 3.9 inches |
| Springfield, Illinois | 1975 | 2.6 inches |
| Springfield, Illinois | 2008 | 2.6 inches |
| Belleville, Illinois | 2007 | 2.6 inches |
| Peoria, Illinois | 2008 | 2.3 inches |