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Boone County, IL Climate
1991 to 2020 normals at Marengo, 12 mi from the center of Boone County, elevation 815 ft.
Average weather by month
Select a month for daily normals and last year's weather
| Month | Range | High | Low | Precip. | Snow |
|---|---|---|---|---|---|
| January | 29° | 13° | 1.67 in | 8.0 in | |
| February | 33° | 16° | 1.64 in | 9.1 in | |
| March | 45° | 26° | 2.08 in | 2.4 in | |
| April | 59° | 36° | 3.81 in | 0.4 in | |
| May | 70° | 47° | 4.57 in | 0.0 in | |
| June | 80° | 57° | 4.62 in | 0.0 in | |
| July | 84° | 62° | 4.05 in | 0.0 in | |
| August | 82° | 60° | 4.22 in | 0.0 in | |
| September | 75° | 52° | 3.68 in | 0.0 in | |
| October | 62° | 40° | 2.98 in | 0.0 in | |
| November | 47° | 29° | 2.35 in | 1.6 in | |
| December | 35° | 19° | 1.94 in | 9.3 in | |
| Year | 58° | 37.61 in | 30.8 in |
Frequently asked questions
- What is the hottest month in Boone County, IL?
- July is the warmest month, with a normal high of 84°F at Marengo.
- What is the coldest month in Boone County, IL?
- January is the coldest month, with a normal low of 13°F.
- What is the wettest month in Boone County, IL?
- June has the most precipitation on average, about 4.62 inches.