Cave-in-Rock State Park is a cave in Hardin County, Illinois. It sits roughly 16.5 km (10.3 mi) NNW of Marion. It is listed on the National Register of Historic Places.
Cave-In-Rock State Park is an Illinois state park, on 204 acres (0.83 km2), in the town of Cave-in-Rock, Hardin County, Illinois, in the United States. The state park contains the historic Cave-In-Rock, a landmark of the Ohio River. It is maintained by the Illinois Department of Natural Resources (IDNR).From the Wikipedia article “Cave-in-Rock State Park”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Cave-in-Rock State Park the sunrise point swings a long way through the year: about 59° (ENE) at the June solstice and 120° (ESE) in late December. Sunset moves from 301° (WNW) in June to 241° (WSW) in December, and the midday sun climbs to 76° in summer but only 29° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 6:57 AM | 90° E | 7:05 PM | 271° W | 52° | 12h 08m |
| June solstice (Jun 21) | 5:33 AM | 59° ENE | 8:18 PM | 301° WNW | 76° | 14h 45m |
| September equinox (Sep 22) | 6:41 AM | 89° E | 6:51 PM | 271° W | 53° | 12h 10m |
| December solstice (Dec 21) | 7:04 AM | 120° ESE | 4:39 PM | 241° WSW | 29° | 9h 34m |
Azimuth is measured clockwise from true north (90° = east, 270° = west). Computed for 2026; values change by less than a degree from year to year.
Golden hour & blue hour by month
Caves are lit artificially — show caves have fixed lighting, so a fast lens and high ISO beat flash, which flattens formations.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 6:38 AM | 7:07 AM | 7:46 AM | 4:19 PM | 4:59 PM | 5:27 PM | 9h 52m |
| February | 6:16 AM | 6:43 AM | 7:19 AM | 4:56 PM | 5:32 PM | 5:59 PM | 10h 50m |
| March | 6:39 AM | 7:05 AM | 7:39 AM | 6:26 PM | 7:00 PM | 7:26 PM | 11h 56m |
| April | 5:52 AM | 6:19 AM | 6:54 AM | 6:53 PM | 7:28 PM | 7:55 PM | 13h 09m |
| May | 5:15 AM | 5:44 AM | 6:22 AM | 7:18 PM | 7:55 PM | 8:25 PM | 14h 11m |
| June | 5:01 AM | 5:32 AM | 6:11 AM | 7:37 PM | 8:16 PM | 8:47 PM | 14h 44m |
| July | 5:14 AM | 5:44 AM | 6:22 AM | 7:36 PM | 8:14 PM | 8:45 PM | 14h 30m |
| August | 5:42 AM | 6:09 AM | 6:45 AM | 7:11 PM | 7:47 PM | 8:14 PM | 13h 37m |
| September | 6:09 AM | 6:35 AM | 7:10 AM | 6:28 PM | 7:02 PM | 7:28 PM | 12h 27m |
| October | 6:35 AM | 7:01 AM | 7:37 AM | 5:42 PM | 6:17 PM | 6:43 PM | 11h 16m |
| November | 6:05 AM | 6:33 AM | 7:11 AM | 4:05 PM | 4:43 PM | 5:11 PM | 10h 10m |
| December | 6:32 AM | 7:01 AM | 7:42 AM | 3:56 PM | 4:36 PM | 5:06 PM | 9h 36m |
Local time (America/Chicago), including daylight saving time. Golden hour runs from about −4° to +6° solar altitude, so the morning golden hour begins during blue hour, before sunrise.
Milky Way & night sky
From Cave-in-Rock State Park, the Milky Way core is visible in a dark sky from March through September. June gives the longest window (about 5.3 hours on a moonless night), and the core peaks around 24° above the southern horizon. Our light-pollution model puts the sky at about Bortle 2 (typical truly dark site), which is excellent for astrophotography.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | -1° | — |
| February | 4:51 AM – 5:11 AM | 0.3 | 13° | SE → SE |
| March | 3:58 AM – 5:28 AM | 1.5 | 20° | SE → SSE |
| April | 2:01 AM – 4:41 AM | 2.7 | 23° | SE → S |
| May | 12:00 AM – 3:50 AM | 3.8 | 24° | SE → S |
| June | 10:10 PM – 3:30 AM | 5.3 | 24° | SE → SSW |
| July | 10:04 PM – 2:04 AM | 4.0 | 24° | SSE → SW |
| August | 9:24 PM – 12:04 AM | 2.7 | 23° | S → SW |
| September | 8:31 PM – 10:01 PM | 1.5 | 20° | SSW → SW |
| October | 7:44 PM – 8:04 PM | 0.3 | 13° | SW → SW |
| November | Below 10° in darkness | — | 1° | — |
| December | Below 10° in darkness | — | -19° | — |
Window when the galactic core is at least 10° high during astronomical darkness on the 15th of each month. Pick nights within a few days of the new moon. Plan exact nights with the Milky Way planner.
Estimated sky darkness: 2 Bortle 2 — Typical truly dark site. The summer Milky Way shows rich structure; clouds look like black holes in the stars. Modeled zenith brightness ≈ 21.7 mag/arcsec². Aurora needs roughly Kp 8.0+ to show low on the northern horizon here.
Weather & best season
Long-term NASA satellite data for this area show September as the clearest month (about 44% average cloud cover) and February as the cloudiest (67%). July is the warmest month and January the coldest, which matters for gear, snow access and how long batteries last at night.
Average cloud cover (%)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| High °F | 71 | 72 | 79 | 85 | 90 | 108 | 109 | 105 | 101 | 94 | 81 | 73 |
| Low °F | -5 | -3 | 5 | 23 | 35 | 43 | 53 | 51 | 39 | 26 | 13 | -3 |
| Precip. (in) | 3.0 | 3.8 | 4.7 | 5.3 | 5.0 | 3.9 | 4.2 | 3.2 | 3.1 | 3.9 | 4.1 | 4.1 |
Monthly climatology for the surrounding 1° grid cell from NASA POWER (MERRA-2). Mountain sites can be colder and cloudier than the cell average.
Photography tips for this cave
- Use manual focus with focus peaking in low light.
- Never touch formations — skin oils stop their growth.
- Follow White-nose Syndrome decontamination rules where posted to protect bats.
- Many show caves restrict tripods on tours; ask in advance or bring a small beanbag.
- Tell someone where you're going in remote areas and carry the ten essentials.
Season: Cave interiors stay at a constant temperature year-round; summer tours fill up, so book ahead.
Suggested gear: Fast lens (f/1.8–f/2.8), High-ISO camera, Small beanbag. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Nearby photo spots
Other locations within 25 km of Cave-in-Rock State Park, closest first.
Campgrounds nearby (Recreation.gov)
FAQ
When is the best time to photograph Cave-in-Rock State Park?
What time is golden hour at Cave-in-Rock State Park?
Where does the sun rise and set at Cave-in-Rock State Park?
Can you see the Milky Way from Cave-in-Rock State Park?
Do you need a permit to photograph at Cave-in-Rock State Park?
How far is Cave-in-Rock State Park from Marion?
Sources
Location data: Wikidata, Wikipedia. Sun, moon and Milky Way times are computed by LWPhoto Atlas for 2026. Climate: NASA POWER. Sky darkness is a population-based estimate (Walker's law), not a measurement. See data sources & licenses.