Illinois
National parks in Illinois
Illinois has no national park, but 1 other busy National Park System site in this guide. The best months below balance mild weather and crowds.
| Park | Best months | Busiest | July high / January low °F | Visitors a year |
|---|---|---|---|---|
| Lincoln Home National Historic Site | Sep | May | 86° / 19° | 146,000 |
Illinois parks by month
| Month | Visitors, all 1 sites | Sites with mild weather |
|---|---|---|
| January | 2,600 | none |
| February | 4,700 | none |
| March | 13,000 | none |
| April | 20,000 | none |
| May | 22,000 | none |
| June | 18,000 | none |
| July | 20,000 | none |
| August | 15,000 | none |
| September | 11,000 | Lincoln Home National Historic Site |
| October | 8,900 | none |
| November | 5,500 | none |
| December | 3,600 | none |
Weather 1991–2020 NOAA normals at each park's nearest station. Visitors National Park Service recreation visits, 2023–2025 average. Mild means an average high of 55–80°F without above-normal rain.