Northern lights in Illinois tonight
The aurora forecast for Illinois, hour by hour: the Kp index NOAA expects, how dark it gets, the Moon and the clouds, for the north of the state (Rockford) where the odds are best.
Unlikely Monday, October 26
The highest Kp expected after dark tonight is 1.67. Rockford (north Illinois) needs about Kp 6 to see the aurora low on the northern horizon, and the sky cover forecast after dark averages 56%. The Moon is 98% lit.
| Time | Sky | Kp | Clouds | Moon | Chance |
|---|---|---|---|---|---|
| 7 PM | Twilight | 1.67 | 71% | 10° | Not dark yet |
| 8 PM | Dark | 1.67 | 71% | 20° | Unlikely |
| 9 PM | Dark | 1.67 | 59% | 31° | Unlikely |
| 10 PM | Dark | 1.33 | 47% | 42° | Unlikely |
| 11 PM | Dark | 1.33 | 36% | 53° | Unlikely |
| 12 AM | Dark | 1.33 | 32% | 62° | Unlikely |
| 1 AM | Dark | 1.33 | 45% | 68° | Unlikely |
| 2 AM | Dark | 1.33 | 51% | 69° | Unlikely |
| 3 AM | Dark | 1.33 | 59% | 63° | Unlikely |
| 4 AM | Dark | 1.33 | 77% | 54° | Clouds in the way |
| 5 AM | Dark | 1.33 | 73% | 44° | Unlikely |
| 6 AM | Dark | 1.33 | 71% | 33° | Unlikely |
Forecast from NOAA SWPC (Kp, 3-hour blocks) and the National Weather Service (sky cover), checked when this page was built. The page updates itself when it can reach our data feed.
What Kp you need in Illinois
The farther north (in magnetic terms) you stand, the lower the Kp you need. From Rockford, an aurora usually shows low on the northern horizon once Kp reaches about 6; overhead displays need about two steps more. A phone camera in night mode often records it one step earlier than the eye. How we estimate this: our method.
How often the aurora reaches Illinois
Our own count from the official Kp archive: on how many nights each year the Kp index reached about 6 or more while it was dark at Rockford. Clouds are not counted, so the real number of nights with a visible aurora is lower. Over the last 10 years the average was 3.1 nights a year; in 2025 it was 8.
Data: Kp index since 1932, GFZ Helmholtz Centre for Geosciences (Matzka et al., 2021), CC BY 4.0. Darkness computed by us for each 3-hour interval (Sun 12° or more below the horizon).
The next 27 days
NOAA's 27-day outlook has no day with a largest Kp near the 6 that Rockford needs. The outlook repeats the Sun's 27-day rotation and cannot see sudden storms, so check the 3-day forecast too.
| Day (UTC) | Largest Kp | At Rockford |
|---|---|---|
| Mon, Oct 26 | 2 | Unlikely |
| Tue, Oct 27 | 2 | Unlikely |
| Wed, Oct 28 | 2 | Unlikely |
| Thu, Oct 29 | 2 | Unlikely |
| Fri, Oct 30 | 2 | Unlikely |
| Sat, Oct 31 | 5 | Low chance |
| Sun, Nov 1 | 4 | Unlikely |
| Mon, Nov 2 | 3 | Unlikely |
| Tue, Nov 3 | 2 | Unlikely |
| Wed, Nov 4 | 2 | Unlikely |
First 10 days shown. Full table: 27-day aurora forecast.
Where to watch in Illinois
Northern Illinois gets a fair shot at the aurora during strong storms, but the Chicago light dome swamps much of the northeast. The northwest corner, along the Mississippi bluffs and near the Wisconsin line, is darker. The Lake Michigan shore faces east, so it helps less than people expect.
Head to open farmland or a bluff with a clear view north. Keep the Chicago glow behind you to the east.
- Mississippi Palisades State Park: bluff state park on the Mississippi River near Savanna
- Apple River Canyon State Park: rural canyon state park near Warren, close to the Wisconsin line
- Rock Cut State Park: lake and woodland state park on the northeast side of Rockford
Cities in Illinois
Nearby states
Questions people ask
Can you see the northern lights in Illinois?
Yes, on active nights. From Rockford it takes about Kp 6, which happened on about 3.1 nights a year over the last 10 years (before clouds).
What time is best?
Usually between 10 pm and 2 am local time, when the sky is fully dark and your location faces the night side of the auroral oval. Storms can bring it earlier or later.
Which way should I look?
North, toward a low, open horizon away from city lights. In strong storms the aurora can climb higher or appear overhead.
Is this an official forecast?
No. It is our estimate built from NOAA's Kp forecast, the National Weather Service sky cover forecast and the Sun and Moon positions. It is not a promise.
Sources: Kp forecast and 27-day outlook: NOAA Space Weather Prediction Center (public domain). Sky cover: National Weather Service (public domain). Kp archive: GFZ, CC BY 4.0. Coordinates: U.S. Census Bureau Gazetteer. Magnetic latitude: our calculation from the IGRF-14 model of Earth's magnetic field. Sun and Moon: Astronomy Engine. Unofficial estimates, not a guarantee.
Page checked: October 26, 2026.