Onyx Cave is a cave in Carroll County, Arkansas. It sits roughly 6.5 km (4.0 mi) SE of Holiday Island.
Onyx Cave is a small show cave located about 6 miles (9.7 km) east of Eureka Springs, Arkansas. It has been a tourist attraction since 1893, making it the oldest show cave in Arkansas. The cave does not contain onyx, but rather flowstone, also known as "cave onyx". During the 19th century and the beginning of the 20th century many such caves were named similarly. Visitors are guided through the cave by audio head sets which inform them about chambers and rock formations. Since the cave has only one public opening, visitors exit the cave the way they entered. The cave stays at an average temperature of 57 °F (14 °C) year round. In 1969, some scenes from the B-movie 'It's Alive' were filmed at Onyx Cave. In October 2017 the cave and surrounding acreage were put for sale for $500,000.From the Wikipedia article “Onyx Cave (Arkansas)”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Onyx Cave the sunrise point swings a long way through the year: about 60° (ENE) at the June solstice and 119° (ESE) in late December. Sunset moves from 300° (WNW) in June to 241° (WSW) in December, and the midday sun climbs to 77° in summer but only 30° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 7:19 AM | 90° E | 7:27 PM | 271° W | 53° | 12h 08m |
| June solstice (Jun 21) | 5:58 AM | 60° ENE | 8:37 PM | 300° WNW | 77° | 14h 39m |
| September equinox (Sep 22) | 7:03 AM | 89° E | 7:13 PM | 271° W | 54° | 12h 10m |
| December solstice (Dec 21) | 7:24 AM | 119° ESE | 5:04 PM | 241° WSW | 30° | 9h 40m |
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 | 6:58 AM | 7:26 AM | 8:05 AM | 4:44 PM | 5:23 PM | 5:51 PM | 9h 57m |
| February | 6:37 AM | 7:04 AM | 7:39 AM | 5:20 PM | 5:56 PM | 6:22 PM | 10h 52m |
| March | 7:01 AM | 7:27 AM | 8:01 AM | 6:48 PM | 7:22 PM | 7:48 PM | 11h 56m |
| April | 6:15 AM | 6:42 AM | 7:16 AM | 7:14 PM | 7:49 PM | 8:15 PM | 13h 07m |
| May | 5:40 AM | 6:09 AM | 6:45 AM | 7:38 PM | 8:15 PM | 8:44 PM | 14h 06m |
| June | 5:27 AM | 5:57 AM | 6:35 AM | 7:57 PM | 8:35 PM | 9:06 PM | 14h 38m |
| July | 5:39 AM | 6:09 AM | 6:46 AM | 7:56 PM | 8:34 PM | 9:03 PM | 14h 25m |
| August | 6:06 AM | 6:33 AM | 7:09 AM | 7:32 PM | 8:07 PM | 8:34 PM | 13h 34m |
| September | 6:32 AM | 6:58 AM | 7:32 AM | 6:50 PM | 7:24 PM | 7:50 PM | 12h 26m |
| October | 6:56 AM | 7:22 AM | 7:57 AM | 6:05 PM | 6:40 PM | 7:06 PM | 11h 17m |
| November | 6:26 AM | 6:53 AM | 7:31 AM | 4:30 PM | 5:08 PM | 5:35 PM | 10h 15m |
| December | 6:51 AM | 7:20 AM | 8:00 AM | 4:21 PM | 5:01 PM | 5:30 PM | 9h 41m |
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 Onyx Cave, the Milky Way core is visible in a dark sky from February through October. June gives the longest window (about 5.5 hours on a moonless night), and the core peaks around 25° above the southern horizon. Our light-pollution model puts the sky at about Bortle 3 (rural sky), good enough for detailed Milky Way images.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | 0° | — |
| February | 5:03 AM – 5:33 AM | 0.5 | 14° | SE → SE |
| March | 4:19 AM – 5:59 AM | 1.7 | 21° | SE → SSE |
| April | 2:10 AM – 5:00 AM | 2.8 | 24° | SE → S |
| May | 12:17 AM – 4:17 AM | 4.0 | 25° | SE → SSW |
| June | 10:26 PM – 3:56 AM | 5.5 | 25° | SE → SW |
| July | 10:21 PM – 2:41 AM | 4.3 | 25° | SSE → SW |
| August | 9:42 PM – 12:32 AM | 2.8 | 24° | S → SW |
| September | 8:51 PM – 10:31 PM | 1.7 | 21° | SSW → SW |
| October | 8:06 PM – 8:36 PM | 0.5 | 14° | 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: 3 Bortle 3 — Rural sky. Some light domes sit on the horizon, but the Milky Way still looks complex overhead. Modeled zenith brightness ≈ 21.57 mag/arcsec².
Weather & best season
Long-term NASA satellite data for this area show September as the clearest month (about 42% average cloud cover) and February as the cloudiest (62%). 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 | 72 | 76 | 83 | 92 | 94 | 107 | 107 | 112 | 101 | 90 | 81 | 73 |
| Low °F | -5 | -5 | 5 | 21 | 33 | 48 | 53 | 50 | 40 | 24 | 11 | 2 |
| Precip. (in) | 2.5 | 2.9 | 4.2 | 5.1 | 5.7 | 4.2 | 3.7 | 3.6 | 3.8 | 4.2 | 3.2 | 2.8 |
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.
- Check road and trail conditions with the managing agency before you go.
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 Onyx Cave, closest first.
Ghost Town
Botanical GardenGhost Town
Cave
Waterfall
State Park
Natural ArchCampgrounds nearby (Recreation.gov)
- Eagle Rock10.4 km (6.5 mi) · reservable
- Big M13.0 km (8.1 mi) · reservable
- Dam Site River (Beaver Lake)14.6 km (9.1 mi) · reservable
- Dam Site Lake Campground15.5 km (9.6 mi) · reservable
- Viola15.6 km (9.7 mi) · reservable
FAQ
When is the best time to photograph Onyx Cave?
What time is golden hour at Onyx Cave?
Where does the sun rise and set at Onyx Cave?
Can you see the Milky Way from Onyx Cave?
Do you need a permit to photograph at Onyx Cave?
How far is Onyx Cave from Holiday Island?
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.