Located in San Bernardino County, California, Clark Mountain Natural Arch is a natural arch at about 2,009 m (6,591 ft) above sea level. The nearest town is Sandy Valley, about 31 km (19 mi) away (Clark Mountain Natural Arch lies S of town).
Sunrise & sunset directions
At Clark Mountain Natural Arch 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 242° (WSW) in December, and the midday sun climbs to 78° in summer but only 31° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 6:47 AM | 90° E | 6:54 PM | 271° W | 54° | 12h 08m |
| June solstice (Jun 21) | 5:28 AM | 60° ENE | 8:02 PM | 300° WNW | 78° | 14h 34m |
| September equinox (Sep 22) | 6:31 AM | 89° E | 6:41 PM | 271° W | 55° | 12h 10m |
| December solstice (Dec 21) | 6:49 AM | 119° ESE | 4:34 PM | 242° WSW | 31° | 9h 45m |
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
Arches glow when reflected light bounces off nearby rock — the underside of an arch often turns bright orange just after sunrise or before sunset.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 6:24 AM | 6:52 AM | 7:30 AM | 4:15 PM | 4:53 PM | 5:21 PM | 10h 01m |
| February | 6:04 AM | 6:30 AM | 7:05 AM | 4:50 PM | 5:25 PM | 5:51 PM | 10h 55m |
| March | 6:29 AM | 6:54 AM | 7:28 AM | 6:17 PM | 6:50 PM | 7:16 PM | 11h 56m |
| April | 5:44 AM | 6:10 AM | 6:44 AM | 6:41 PM | 7:16 PM | 7:42 PM | 13h 05m |
| May | 5:10 AM | 5:38 AM | 6:15 AM | 7:05 PM | 7:41 PM | 8:09 PM | 14h 02m |
| June | 4:57 AM | 5:27 AM | 6:05 AM | 7:22 PM | 8:00 PM | 8:30 PM | 14h 33m |
| July | 5:10 AM | 5:39 AM | 6:16 AM | 7:22 PM | 7:59 PM | 8:28 PM | 14h 20m |
| August | 5:35 AM | 6:02 AM | 6:37 AM | 6:58 PM | 7:33 PM | 8:00 PM | 13h 31m |
| September | 6:00 AM | 6:26 AM | 6:59 AM | 6:17 PM | 6:51 PM | 7:17 PM | 12h 25m |
| October | 6:24 AM | 6:49 AM | 7:24 AM | 5:34 PM | 6:08 PM | 6:34 PM | 11h 19m |
| November | 5:52 AM | 6:19 AM | 6:56 AM | 4:00 PM | 4:37 PM | 5:04 PM | 10h 18m |
| December | 6:17 AM | 6:45 AM | 7:25 AM | 3:52 PM | 4:31 PM | 5:00 PM | 9h 46m |
Local time (America/Los Angeles), 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 Clark Mountain Natural Arch, the Milky Way core is visible in a dark sky from February through October. June gives the longest window (about 5.8 hours on a moonless night), and the core peaks around 26° 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 | — | -1° | — |
| February | 4:30 AM – 5:00 AM | 0.5 | 15° | SE → SE |
| March | 3:35 AM – 5:25 AM | 1.8 | 22° | SE → SSE |
| April | 1:35 AM – 4:35 AM | 3.0 | 25° | SE → S |
| May | 11:40 PM – 3:50 AM | 4.2 | 26° | SE → SSW |
| June | 9:48 PM – 3:38 AM | 5.8 | 26° | SE → SW |
| July | 9:43 PM – 2:13 AM | 4.5 | 26° | SSE → SW |
| August | 9:06 PM – 12:06 AM | 3.0 | 25° | S → SW |
| September | 8:17 PM – 10:07 PM | 1.8 | 22° | SSW → SW |
| October | 7:33 PM – 8:03 PM | 0.5 | 15° | SW → SW |
| November | Below 10° in darkness | — | 2° | — |
| 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 ≈ 21.56 mag/arcsec².
Weather & best season
Long-term NASA satellite data for this area show June as the clearest month (about 17% average cloud cover) and December as the cloudiest (44%). July is the warmest month and December 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 | 76 | 77 | 87 | 95 | 104 | 110 | 110 | 108 | 108 | 96 | 83 | 73 |
| Low °F | 17 | 19 | 23 | 29 | 35 | 44 | 57 | 51 | 41 | 26 | 21 | 20 |
| Precip. (in) | 0.7 | 1.1 | 0.5 | 0.4 | 0.1 | 0.0 | 0.7 | 0.7 | 0.4 | 0.5 | 0.6 | 0.8 |
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 natural arch
- At night, arches make classic Milky Way foregrounds; low-level lighting or blue hour exposures keep the rock detailed.
- Use a wide lens and get close to emphasize the span against the sky.
- Never climb on arches; many are fragile and climbing is prohibited on park lands.
- Midday sun creates hard shadows, but can light the underside through reflection in narrow canyons.
- Tell someone where you're going in remote areas and carry the ten essentials.
Season: Spring and autumn offer mild temperatures in desert arch country; summer heat is extreme at midday.
Suggested gear: Ultra-wide lens, Tripod, Headlamp, Plenty of water. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Nearby photo spots
Other locations within 25 km of Clark Mountain Natural Arch, closest first.
FAQ
When is the best time to photograph Clark Mountain Natural Arch?
What time is golden hour at Clark Mountain Natural Arch?
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How far is Clark Mountain Natural Arch from Sandy Valley?
Sources
Location data: USGS GNIS / GeoNames. 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.