Northern lights in Illinois tonight
Illinois, USA · 51° magnetic latitude · Kp 5-6 threshold
Kp 1 is well below the Kp 5-6 threshold needed for aurora to be visible from Illinois.
7-day outlook for Illinois
Based on CME arrival predictions from NASA DONKI. Arrival times ±6 hours.
auroratonight.space
What Kp is needed here?
Illinois sits at a magnetic latitude of approximately 51°N. The Kp index - a global measure of geomagnetic activity on a scale from 0 (quiet) to 9 (extreme storm), updated every 3 hours - needs to reach Kp 5-6 before the auroral oval expands far enough south to be visible from here.
At Kp 5-6, visibility is possible from Illinois but skies need to be clear and dark. Cloud cover and light pollution remain the main obstacles even when Kp is high enough.
Best dark sky sites near Illinois
Light pollution is the biggest obstacle after cloud cover. These sites give you the best dark northern horizon within reach.
Nachusa Grasslands (The Nature Conservancy)
Get directions ↗A 4000-acre restored tallgrass prairie in Lee County, west-central Illinois. The open prairie gives a full 360-degree sky with no light domes to the north or west. Bortle 3 conditions. About 100 miles from Chicago via I-88 and US-30. The flat prairie horizon suits aurora viewing: a low glow to the north is visible with no terrain or tree obstructions when a Kp 5-6 storm is in progress. The Nature Conservancy site is open to visitors.
Starved Rock State Park / Matthiessen area
Get directions ↗The canyons and forested ridges along the Illinois River give Bortle 3-4 conditions. North-facing ridge positions above the gorges give open sky. About 95 miles from Chicago via I-80. Popular destination - the parking areas above the canyon rims give the clearest north-facing positions. The narrow forested canyon floor can obstruct sky significantly; positions on the rim work better for aurora.
Shawnee National Forest - Garden of the Gods
Get directions ↗Southern Illinois along the Ohio River sits markedly darker than the north. Garden of the Gods gives Bortle 2 sky from the sandstone formations. The geographic latitude here is 37.6°N, around 46° geomagnetic latitude - lower than Chicago, so an even stronger storm is needed. A long drive from Chicago at 330 miles; better suited to observers based near St Louis or in western Kentucky. For a major storm, the Bortle 2 conditions and striking rock formations make it a strong site.
Moraine Hills State Park / Chain O'Lakes area
Get directions ↗The lake country of northeastern Illinois near the Wisconsin border gives the state's highest latitude positions at 42.3°N geographic. Chain O'Lakes State Park and Moraine Hills face north with reasonable darkness given proximity to Chicago. Not dark enough for a faint glow, but useful during a Kp 5-6 storm when the display is bright enough to register against residual sky glow. About 45 miles from Chicago.
Best time to see the northern lights in Illinois
At 51°N magnetic latitude, Illinois sits at the lower end of regular aurora territory. Only the deep mid-winter months of November through January offer nights dark enough for aurora to be visible, and only then when a significant geomagnetic storm pushes the auroral oval this far south.
Activity peaks around the September and March equinoxes, when Earth's magnetic field geometry is most favourable for coupling with the solar wind. Events during these two windows tend to produce the strongest displays of the year for observers at Illinois's latitude.
Outside November through January, twilight is too bright for aurora viewing even during significant storms. The season is short, but the equinox months on either side of winter can extend it slightly when storm timing aligns.
Related pages
Northern Lights USA
USA-wide aurora forecast hub.
Read →Northern Lights Iowa Tonight
Iowa - flat open sky and Bortle 3 in the west.
Read →Northern Lights Indiana Tonight
Indiana - Indiana Dunes on Lake Michigan.
Read →Northern Lights Minnesota Tonight
Minnesota - Boundary Waters, higher latitude and darker sky.
Read →What Is the Kp Index?
What Kp 5-6 means for viewing at 51° geomagnetic latitude.
Read →Aurora photographs from Illinois
Real photos sourced from Wikimedia Commons.
Aurora over Illinois
Aurora over Illinois
Aurora over Illinois
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