Located in San Bernardino County, California, Slover Mountain is a mountain peak at about 361 m (1,184 ft) above sea level. It sits roughly 2.8 km (1.7 mi) WSW of Colton.
Slover Mountain (Mount Slover, Marble Mountain) is a former mountain in Colton, in southwestern San Bernardino County and the Inland Empire region of Southern California. Now a hill, it was surface mined for limestone in the 20th century. The Colton Joint Unified School District's continuation high school is named after the mountain. The mountain was known as Tahualtapa ("raven hill") by Native Americans and Cerrito Solo ("little solitary hill") by the colonial Spanish.From the Wikipedia article “Slover Mountain”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Slover Mountain the sunrise point swings a long way through the year: about 61° (ENE) at the June solstice and 118° (ESE) in late December. Sunset moves from 299° (WNW) in June to 242° (WSW) in December, and the midday sun climbs to 79° in summer but only 33° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 6:54 AM | 90° E | 7:01 PM | 271° W | 56° | 12h 08m |
| June solstice (Jun 21) | 5:39 AM | 61° ENE | 8:05 PM | 299° WNW | 79° | 14h 26m |
| September equinox (Sep 22) | 6:38 AM | 89° E | 6:48 PM | 271° W | 56° | 12h 09m |
| December solstice (Dec 21) | 6:52 AM | 118° ESE | 4:45 PM | 242° WSW | 33° | 9h 53m |
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
Summits catch first and last light — alpenglow can turn rock pink or orange minutes before sunrise and after sunset while valleys stay in shadow.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 6:28 AM | 6:55 AM | 7:33 AM | 4:26 PM | 5:03 PM | 5:31 PM | 10h 08m |
| February | 6:09 AM | 6:35 AM | 7:10 AM | 4:59 PM | 5:34 PM | 5:59 PM | 10h 59m |
| March | 6:36 AM | 7:01 AM | 7:34 AM | 6:24 PM | 6:58 PM | 7:23 PM | 11h 57m |
| April | 5:53 AM | 6:19 AM | 6:52 AM | 6:47 PM | 7:21 PM | 7:47 PM | 13h 02m |
| May | 5:21 AM | 5:49 AM | 6:24 AM | 7:09 PM | 7:45 PM | 8:12 PM | 13h 56m |
| June | 5:09 AM | 5:38 AM | 6:15 AM | 7:26 PM | 8:03 PM | 8:32 PM | 14h 25m |
| July | 5:21 AM | 5:50 AM | 6:26 AM | 7:26 PM | 8:02 PM | 8:31 PM | 14h 13m |
| August | 5:45 AM | 6:12 AM | 6:46 AM | 7:04 PM | 7:38 PM | 8:04 PM | 13h 26m |
| September | 6:08 AM | 6:33 AM | 7:06 AM | 6:25 PM | 6:58 PM | 7:23 PM | 12h 24m |
| October | 6:30 AM | 6:55 AM | 7:29 AM | 5:43 PM | 6:16 PM | 6:42 PM | 11h 21m |
| November | 5:56 AM | 6:23 AM | 6:59 AM | 4:11 PM | 4:47 PM | 5:13 PM | 10h 24m |
| December | 6:21 AM | 6:48 AM | 7:27 AM | 4:04 PM | 4:42 PM | 5:10 PM | 9h 54m |
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 Slover Mountain, the Milky Way core is visible in a dark sky from February through October. June gives the longest window (about 6.0 hours on a moonless night), and the core peaks around 27° above the southern horizon. Our light-pollution model puts the sky at about Bortle 8 (city sky), so expect visible sky glow; drive away from towns for better results.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | 0° | — |
| February | 4:27 AM – 5:07 AM | 0.7 | 16° | SE → SE |
| March | 3:40 AM – 5:30 AM | 1.8 | 24° | SE → SSE |
| April | 1:38 AM – 4:48 AM | 3.2 | 27° | SE → S |
| May | 11:41 PM – 4:01 AM | 4.3 | 27° | SE → SSW |
| June | 9:47 PM – 3:47 AM | 6.0 | 27° | SE → SW |
| July | 9:43 PM – 2:23 AM | 4.7 | 27° | SSE → SW |
| August | 9:08 PM – 12:18 AM | 3.2 | 27° | S → SW |
| September | 8:21 PM – 10:21 PM | 2.0 | 24° | SSW → SW |
| October | 7:39 PM – 8:19 PM | 0.7 | 16° | SW → SW |
| November | Below 10° in darkness | — | 2° | — |
| December | Below 10° in darkness | — | -18° | — |
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: 8 Bortle 8 — City sky. Only bright constellations are visible; the sky glows orange or white. Modeled zenith brightness ≈ 18.07 mag/arcsec².
Weather & best season
Long-term NASA satellite data for this area show September as the clearest month (about 14% average cloud cover) and January 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 | 77 | 82 | 87 | 93 | 103 | 110 | 111 | 109 | 109 | 98 | 86 | 78 |
| Low °F | 22 | 22 | 24 | 27 | 35 | 40 | 51 | 48 | 40 | 33 | 24 | 20 |
| Precip. (in) | 1.8 | 2.0 | 1.1 | 0.6 | 0.2 | 0.0 | 0.2 | 0.1 | 0.1 | 0.5 | 0.8 | 1.8 |
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 mountain peak
- Snow on the summit holds detail best when you expose for the highlights and lift shadows later.
- Alpenglow lasts only a few minutes; set up and focus beforehand.
- Clouds around the summit add drama — a clear blue sky is often the least interesting condition.
- Photograph the peak from a lake, meadow or ridge at sunrise when the face that looks east lights up first.
- Long lenses compress ridgelines; shoot the peak from several miles away to make it look massive.
- Shoot RAW to keep the most latitude for high-contrast sunrise and sunset scenes.
Season: Early summer keeps snow on the peaks with green valleys below; autumn adds aspen or larch color in many ranges.
Suggested gear: Telephoto lens, Lightweight tripod, Warm layers, Microspikes in shoulder seasons. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Nearby photo spots
Other locations within 25 km of Slover Mountain, closest first.
Hot Spring
Hot Spring
Mountain Peak
Botanical Garden
Canyon
Canyon
Canyon
State Park
Scenic ViewpointCampgrounds nearby (Recreation.gov)
- Dogwood 22 km (14 mi) · reservable
- Applewhite Campground26 km (16 mi)
- Applewhite Campground (Ca)26 km (16 mi) · reservable
- North Shore (Ca)28 km (17 mi) · reservable
- Fishermans Group29 km (18 mi) · reservable
FAQ
When is the best time to photograph Slover Mountain?
What time is golden hour at Slover Mountain?
Where does the sun rise and set at Slover Mountain?
Can you see the Milky Way from Slover Mountain?
Do you need a permit to photograph at Slover Mountain?
How far is Slover Mountain from Colton?
Sources
Location data: Wikidata, USGS GNIS / GeoNames, 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.