Peak UV index by city
| City | Population | Peak UV | Exposure | UV 3+ hours |
|---|---|---|---|---|
| Chicago | 2,731,585 | 2 | Low | Below 3 all day |
| Aurora | 181,505 | 1 | Low | Below 3 all day |
| Naperville | 153,114 | 1 | Low | Below 3 all day |
| Joliet | 152,241 | 1 | Low | Below 3 all day |
| Rockford | 147,384 | 1 | Low | Below 3 all day |
| Elgin | 115,476 | 1 | Low | Below 3 all day |
| Springfield | 112,989 | 2 | Low | Below 3 all day |
| Peoria | 110,920 | 1 | Low | Below 3 all day |
| Champaign | 91,195 | 2 | Low | Below 3 all day |
| Waukegan | 87,940 | 1 | Low | Below 3 all day |
| Cicero | 81,858 | 2 | Low | Below 3 all day |
| Bloomington | 78,804 | 2 | Low | Below 3 all day |
| Schaumburg | 77,249 | 1 | Low | Below 3 all day |
| Evanston | 76,380 | 1 | Low | Below 3 all day |
| Arlington Heights | 76,216 | 1 | Low | Below 3 all day |
| Bolingbrook | 74,803 | 1 | Low | Below 3 all day |
| Decatur | 67,884 | 2 | Low | Below 3 all day |
| Skokie | 66,544 | 1 | Low | Below 3 all day |
| Palatine | 65,842 | 1 | Low | Below 3 all day |
| Des Plaines | 58,772 | 1 | Low | Below 3 all day |
| Orland Park | 57,954 | 2 | Low | Below 3 all day |
| Oak Lawn | 56,450 | 2 | Low | Below 3 all day |
| Mount Prospect | 55,395 | 1 | Low | Below 3 all day |
| Tinley Park | 55,140 | 2 | Low | Below 3 all day |
| Berwyn | 55,001 | 2 | Low | Below 3 all day |
| Wheaton | 54,065 | 1 | Low | Below 3 all day |
| Normal | 53,275 | 2 | Low | Below 3 all day |
| Oak Park | 52,823 | 1 | Low | Below 3 all day |
| Hoffman Estates | 50,858 | 1 | Low | Below 3 all day |
| Downers Grove | 50,365 | 1 | Low | Below 3 all day |
| Plainfield | 50,043 | 1 | Low | Below 3 all day |
| Glenview | 47,711 | 1 | Low | Below 3 all day |
| Elmhurst | 46,111 | 1 | Low | Below 3 all day |
| Lombard | 44,399 | 1 | Low | Below 3 all day |
| Buffalo Grove | 42,812 | 1 | Low | Below 3 all day |
| Moline | 42,362 | 1 | Low | Below 3 all day |
| Crystal Lake | 42,288 | 1 | Low | Below 3 all day |
| Romeoville | 41,281 | 1 | Low | Below 3 all day |
| Bartlett | 40,855 | 1 | Low | Below 3 all day |
| DeKalb | 40,467 | 1 | Low | Below 3 all day |
| Belleville | 40,237 | 2 | Low | Below 3 all day |
| Oswego | 39,948 | 1 | Low | Below 3 all day |
| Urbana | 39,719 | 2 | Low | Below 3 all day |
| Carol Stream | 39,315 | 1 | Low | Below 3 all day |
| Quincy | 38,918 | 1 | Low | Below 3 all day |
| Park Ridge | 38,463 | 1 | Low | Below 3 all day |
| Wheeling | 38,391 | 1 | Low | Below 3 all day |
| Streamwood | 38,277 | 1 | Low | Below 3 all day |
| Carpentersville | 37,045 | 1 | Low | Below 3 all day |
| Hanover Park | 36,568 | 1 | Low | Below 3 all day |
| Rock Island | 36,225 | 1 | Low | Below 3 all day |
| Addison | 35,758 | 1 | Low | Below 3 all day |
| Calumet City | 34,798 | 2 | Low | Below 3 all day |
| Northbrook | 34,744 | 1 | Low | Below 3 all day |
| North Chicago | 34,050 | 1 | Low | Below 3 all day |
| Woodridge | 34,028 | 1 | Low | Below 3 all day |
| St. Charles | 33,594 | 1 | Low | Below 3 all day |
| Mundelein | 32,680 | 1 | Low | Below 3 all day |
| O'Fallon | 32,656 | 2 | Low | Below 3 all day |
| Glendale Heights | 32,655 | 1 | Low | Below 3 all day |
| Elk Grove Village | 31,885 | 1 | Low | Below 3 all day |
| Pekin | 31,277 | 2 | Low | Below 3 all day |
| Algonquin | 30,824 | 1 | Low | Below 3 all day |
| Highland Park | 30,767 | 1 | Low | Below 3 all day |
| Gurnee | 30,458 | 1 | Low | Below 3 all day |
| Niles | 30,443 | 1 | Low | Below 3 all day |
| McHenry | 29,217 | 1 | Low | Below 3 all day |
| Huntley | 29,132 | 1 | Low | Below 3 all day |
| New Lenox | 28,893 | 1 | Low | Below 3 all day |
| Glen Ellyn | 28,750 | 1 | Low | Below 3 all day |
| Lake in the Hills | 28,590 | 1 | Low | Below 3 all day |
| Galesburg | 28,581 | 1 | Low | Below 3 all day |
| Burbank | 28,578 | 2 | Low | Below 3 all day |
| Danville | 28,138 | 2 | Low | Below 3 all day |
| Lansing | 28,068 | 2 | Low | Below 3 all day |
| Lockport | 27,822 | 1 | Low | Below 3 all day |
| Wilmette | 27,459 | 1 | Low | Below 3 all day |
| Round Lake Beach | 26,902 | 1 | Low | Below 3 all day |
| Vernon Hills | 26,825 | 1 | Low | Below 3 all day |
| Granite City | 26,807 | 2 | Low | Below 3 all day |
| Oak Forest | 26,792 | 2 | Low | Below 3 all day |
| Yorkville | 26,730 | 1 | Low | Below 3 all day |
| Batavia | 26,586 | 1 | Low | Below 3 all day |
| Chicago Heights | 26,508 | 2 | Low | Below 3 all day |
| Edwardsville | 26,463 | 2 | Low | Below 3 all day |
| Woodstock | 25,740 | 1 | Low | Below 3 all day |
| South Elgin | 25,656 | 1 | Low | Below 3 all day |
| Belvidere | 25,462 | 2 | Low | Below 3 all day |
| West Chicago | 25,296 | 1 | Low | Below 3 all day |
| Alton | 25,013 | 2 | Low | Below 3 all day |
UV 3+ hours show the window from the first forecast hour at 3 or above to the end of the last. The EPA recommends sun protection at UV 3 and above. Open a city for its current-hour forecast and hourly chart. Forecast sources and limitations.
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