Can you see the northern lights in Illinois tonight?
Tonight is worth a look: Kp 5.33 at 3:37 PM CDT meets or clears the Kp 5 threshold for Illinois.
as of
Kp now
5.33
Illinois needs
Kp 5
Verdict
Possible
Sky tonight
Clear, 4% cloud
Moon tonight
41% lit, last quarter
Nautical darkness
Darkness 7:27 PM to 5:52 AM
Kp from NOAA SWPC estimated planetary K index. The NWS LOT gridded forecast provides cloud cover for Illinois Beach State Park.
At Illinois Beach State Park, nautical darkness begins at 7:27 PM and holds until 5:52 AM CDT. Tonight's moon, in its last quarter phase, shows 41 percent lit. The sun and moon positions, computed for the date and the viewing spot, supply both numbers, and no forecast plays a part.
What is Kp?
A 0-9 scale called Kp rates the current disturbance of Earth's magnetic field. Its name comes from planetarische Kennziffer, German for planetary index. Thirteen observatories worldwide take the measurements. Higher values mean the aurora reaches further south. Most of the northern US needs a Kp of 5 or higher, while northern Alaska sees it at Kp 0. Full Kp guide.
Why Illinois needs Kp 5
Because the aurora follows the magnetic field rather than the equator, geomagnetic latitude matters more than map latitude. At Illinois's northern edge, the reading is 51.4° geomagnetic; the oval only draws level with that latitude at about Kp 5, and the Kp number already includes roughly 5 degrees of cushion, because the high-altitude aurora hangs low on the horizon.
Where to watch from in Illinois
All three spots in Illinois can differ in cloud cover, so all three are worth a look. Rock Cut State Park looks clearest tonight, at 2% cover.
| Spot | Cloud tonight | Clearest hour | Nearest town |
|---|---|---|---|
| Illinois Beach State Park | 4% Clear | 9:00 PM CDT | Beach Park |
| Rock Cut State Park | 2% Clear | 11:00 PM CDT | Loves Park |
| Apple River Canyon State Park | 5% Clear | 9:00 PM CDT | Warren |
A NOAA G1 minor storm can put northern lights over Illinois, something that happens about 900 days per cycle. Illinois Beach State Park near Beach Park faces Lake Michigan, and Apple River Canyon State Park near Warren offers darker western sky. Rock Cut State Park near Loves Park is a third option.
Can the northern lights reach Chicago and Peoria tonight?
| City | Kp needed | Right now |
|---|---|---|
| Chicago | Kp 6 | Possible |
| Peoria | Kp 6 | Unlikely |
Each city's Kp value comes from its own coordinates and geomagnetic latitude, so the further south a city is in the state, the higher the Kp it needs.
Cloud cover, averaged over tonight's viewing window for each location, comes from NWS gridded forecasts.
Was there aurora last night in Illinois?
The night of October 3 topped out at Kp 3.00, short of the 5 Illinois needs, so the aurora stayed out of range.
The most recent night in range was July 3, 2026, when the night's highest Kp reached 6.00.
17 nights so far in 2026 have been in range for Illinois, against a yearly average of 20.4 across the complete years since 1994. The year's highest night Kp so far is 8.67, set on January 19, 2026.
Nights in range by year in Illinois
| Year | Nights in range | Highest Kp | Peak date |
|---|---|---|---|
| 2026 2026 is not over | 17 | 8.67 | Jan 19, 2026 |
| 2025 | 42 | 8.67 | Nov 11, 2025 |
| 2024 | 18 | 9.00 | May 10, 2024 |
| 2023 | 16 | 7.67 | Apr 23, 2023 |
| 2022 | 24 | 6.00 | Jan 14, 2022 |
| 2021 | 13 | 7.00 | Nov 3, 2021 |
| 2020 | 2 | 6.00 | Sep 27, 2020 |
| 2019 | 10 | 5.00 | Jan 4, 2019 |
| 2018 | 14 | 6.00 | Mar 18, 2018 |
| 2017 | 30 | 8.00 | Sep 7, 2017 |
| 2016 | 35 | 7.00 | Mar 6, 2016 |
| 2015 | 36 | 8.00 | Mar 17, 2015 |
Local time 9 pm to 3 am is the span of a night. The night's Kp is the highest among the three hour windows overlapping those hours. A night is in range when that Kp reached the threshold the state needs, which comes from where the northern edge of the state sits in geomagnetic latitude. Cloud is not in the record, so in range means the aurora was in range, not that anyone saw it. Figures are NOAA Space Weather Prediction Center daily geomagnetic data from 1994 on.
The next three days
NOAA's three-hour Kp outlook. At the highest expected value of Kp 5.00, the aurora would come into range for Illinois.
| Day | Local window | Kp | In range |
|---|---|---|---|
| Oct 3 | 7 PM to 10 PM CDT00-03UT | 3.00 | No |
| Oct 3 | 10 PM to 1 AM CDT03-06UT | 3.33 | No |
| Oct 4 | 1 AM to 4 AM CDT06-09UT | 4.33 | No |
| Oct 4 | 4 AM to 7 AM CDT09-12UT | 5.00 | Yes |
| Oct 4 | 7 AM to 10 AM CDT12-15UT | 4.00 | No |
| Oct 4 | 10 AM to 1 PM CDT15-18UT | 3.67 | No |
| Oct 4 | 1 PM to 4 PM CDT18-21UT | 4.67 | No |
| Oct 4 | 4 PM to 7 PM CDT21-00UT | 3.00 | No |
| Oct 4 | 7 PM to 10 PM CDT00-03UT | 3.33 | No |
| Oct 4 | 10 PM to 1 AM CDT03-06UT | 4.33 | No |
| Oct 5 | 1 AM to 4 AM CDT06-09UT | 3.33 | No |
| Oct 5 | 7 AM to 10 AM CDT12-15UT | 2.67 | No |
| Oct 5 | 10 AM to 1 PM CDT15-18UT | 1.67 | No |
| Oct 5 | 4 PM to 7 PM CDT21-00UT | 3.00 | No |
| Oct 5 | 7 PM to 10 PM CDT00-03UT | 3.33 | No |
| Oct 5 | 10 PM to 1 AM CDT03-06UT | 3.67 | No |
| Oct 6 | 1 AM to 4 AM CDT06-09UT | 3.00 | No |
| Oct 6 | 4 AM to 7 AM CDT09-12UT | 3.00 | No |
| Oct 6 | 7 AM to 10 AM CDT12-15UT | 2.33 | No |
| Oct 6 | 10 AM to 1 PM CDT15-18UT | 2.00 | No |
| Oct 6 | 1 PM to 4 PM CDT18-21UT | 2.00 | No |
| Oct 6 | 4 PM to 7 PM CDT21-00UT | 1.67 | No |
NOAA Space Weather Prediction Center three-day forecast, issued 2026 Oct 04 1230 UTC.
The next 27 days
The NOAA Space Weather Prediction Center outlook puts 1 of the next 27 days at or above Kp 5.
This Kp outlook is issued by the NOAA Space Weather Prediction Center at 2026 Sep 28 0221 UTC.
Watching from Illinois
- The aurora seldom appears overhead in Illinois; look at the northern horizon instead.
- Away from town lights, allow 20 minutes for your eyes to adjust.
- The aurora is most active from 10pm to 2am local, near magnetic midnight.
- A phone exposure of 3-5 seconds picks up color the eye cannot; a grey glow can photograph green.
Compare every state, ranked right now
The NOAA Space Weather Prediction Center produces the Kp readings and aurora forecasts on this page. As US government works, they are not subject to copyright under 17 U.S.C. 105; this notice is the notice required by 17 U.S.C. 403. Mention of the center does not imply endorsement or affiliation; for attribution, see Data sources and attribution.