Located in Mono County, California, Red Slate Mountain is a mountain peak at about 4,005 m (13,140 ft) above sea level. It is part of Sierra National Forest. The nearest town is Mammoth Lakes, about 18.1 km (11.2 mi) away (Red Slate Mountain lies SSE of town).
Red Slate Mountain is a summit in the Sierra Nevada. It lies along the Sierra Crest that divides Fresno County from Mono County, California. Red Slate Mountain can be reached by scrambling either from McGee Pass, or starting from Bighorn Lake. The area to the north of Red Slate Mountain is among the most seismically active in California which is associated with the Long Valley Caldera. Red Slate Mountain was named by the California Geological Survey, in 1873. However, it is not clear whether the survey meant to name this peak, or Red and White Mountain.From the Wikipedia article “Red Slate Mountain”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Red Slate Mountain 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) | 7:00 AM | 90° E | 7:08 PM | 271° W | 52° | 12h 08m |
| June solstice (Jun 21) | 5:35 AM | 59° ENE | 8:21 PM | 301° WNW | 76° | 14h 45m |
| September equinox (Sep 22) | 6:44 AM | 89° E | 6:54 PM | 271° W | 53° | 12h 10m |
| December solstice (Dec 21) | 7:07 AM | 120° ESE | 4:41 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
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 | 6:41 AM | 7:10 AM | 7:49 AM | 4:22 PM | 5:01 PM | 5:30 PM | 9h 52m |
| February | 6:19 AM | 6:46 AM | 7:22 AM | 4:59 PM | 5:35 PM | 6:02 PM | 10h 50m |
| March | 6:41 AM | 7:07 AM | 7:42 AM | 6:29 PM | 7:03 PM | 7:29 PM | 11h 56m |
| April | 5:54 AM | 6:21 AM | 6:56 AM | 6:56 PM | 7:31 PM | 7:58 PM | 13h 10m |
| May | 5:18 AM | 5:47 AM | 6:24 AM | 7:21 PM | 7:58 PM | 8:28 PM | 14h 11m |
| June | 5:04 AM | 5:35 AM | 6:14 AM | 7:40 PM | 8:19 PM | 8:50 PM | 14h 44m |
| July | 5:17 AM | 5:47 AM | 6:25 AM | 7:39 PM | 8:17 PM | 8:47 PM | 14h 30m |
| August | 5:44 AM | 6:12 AM | 6:48 AM | 7:14 PM | 7:49 PM | 8:17 PM | 13h 37m |
| September | 6:12 AM | 6:38 AM | 7:13 AM | 6:30 PM | 7:05 PM | 7:31 PM | 12h 27m |
| October | 6:38 AM | 7:04 AM | 7:40 AM | 5:44 PM | 6:20 PM | 6:46 PM | 11h 15m |
| November | 6:08 AM | 6:36 AM | 7:14 AM | 4:08 PM | 4:46 PM | 5:14 PM | 10h 10m |
| December | 6:35 AM | 7:04 AM | 7:45 AM | 3:58 PM | 4:39 PM | 5:08 PM | 9h 35m |
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 Red Slate Mountain, 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 | 4:53 AM – 5:13 AM | 0.3 | 13° | SE → SE |
| March | 4:00 AM – 5:30 AM | 1.5 | 20° | SE → SSE |
| April | 2:03 AM – 4:43 AM | 2.7 | 23° | SE → S |
| May | 12:02 AM – 3:52 AM | 3.8 | 24° | SE → S |
| June | 10:12 PM – 3:32 AM | 5.3 | 24° | SE → SSW |
| July | 10:06 PM – 2:06 AM | 4.0 | 24° | SSE → SW |
| August | 9:26 PM – 12:06 AM | 2.7 | 23° | S → SW |
| September | 8:33 PM – 10:03 PM | 1.5 | 20° | SSW → SW |
| October | 7:46 PM – 8:06 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 ≈ 21.75 mag/arcsec².
Weather & best season
Long-term NASA satellite data for this area show September as the clearest month (about 21% average cloud cover) and December as the cloudiest (54%). 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 | 53 | 60 | 63 | 72 | 79 | 86 | 90 | 88 | 85 | 78 | 68 | 55 |
| Low °F | -14 | -12 | -14 | -3 | 12 | 20 | 35 | 31 | 20 | 9 | -7 | -16 |
| Precip. (in) | 3.8 | 3.8 | 3.0 | 2.0 | 1.2 | 0.4 | 0.4 | 0.2 | 0.2 | 1.3 | 2.0 | 3.9 |
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
- Afternoon thunderstorms are common in summer at high elevations — plan summit hikes for early morning.
- 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.
- Check road and trail conditions with the managing agency before you go.
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 Red Slate Mountain, closest first.
Waterfall
Lake
Lake
Mountain Peak
Lake
Mountain Peak
Mountain PeakLake
Mountain PeakCampgrounds nearby (Recreation.gov)
- Mcgee Creek9.8 km (6.1 mi) · reservable
- Convict Lake Campground10.3 km (6.4 mi) · reservable
- Crowley Lake Campground11.2 km (7.0 mi) · reservable
- Crowley Lake Campground11.2 km (7.0 mi)
- Rock Creek Lake Group Camp (Inyo National Forest, Ca)13.0 km (8.1 mi) · reservable
FAQ
When is the best time to photograph Red Slate Mountain?
What time is golden hour at Red Slate Mountain?
Where does the sun rise and set at Red Slate Mountain?
Can you see the Milky Way from Red Slate Mountain?
Do you need a permit to photograph at Red Slate Mountain?
How far is Red Slate Mountain from Mammoth Lakes?
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.