Located in Gem County, Idaho, Spring Valley Summit is a mountain pass. It sits roughly 12.7 km (7.9 mi) N of Hidden Spring.
Spring Valley Summit is a mountain pass in the western United States in southwestern Idaho, at an elevation of 4,242 feet (1,293 m) above sea level. North of the city of Boise, it is traversed by State Highway 55, the Payette River Scenic Byway. Located in southwestern Boise County, the summit is south of the city of Horseshoe Bend, 1,600 vertical feet (490 m) below. It marks the divide between the Payette River and Boise River drainage areas. The new multi-lane grade of Highway 55 into Horseshoe Bend was completed in the fall of 1991; the old curvier road is to the west, long plagued by landslides and closures. Part of an ancient lake, dozens of springs fed water and undermined the roadway. Of the major grades from Boise to north Idaho, it was the last to be improved. The other three, all on U.S. 95, were White Bird Hill (1975), Lapwai Canyon (1960), and Lewiston Hill (1977). The...From the Wikipedia article “Spring Valley Summit”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Spring Valley Summit the sunrise point swings a long way through the year: about 56° (NE) at the June solstice and 123° (ESE) in late December. Sunset moves from 305° (NW) in June to 238° (WSW) in December, and the midday sun climbs to 70° in summer but only 23° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 7:49 AM | 90° E | 7:58 PM | 271° W | 46° | 12h 09m |
| June solstice (Jun 21) | 6:04 AM | 56° NE | 9:32 PM | 305° NW | 70° | 15h 28m |
| September equinox (Sep 22) | 7:33 AM | 89° E | 7:44 PM | 271° W | 46° | 12h 11m |
| December solstice (Dec 21) | 8:17 AM | 123° ESE | 5:11 PM | 238° WSW | 23° | 8h 54m |
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
Mountain passes sit above valleys, so they reward sunrise and sunset with layered ridges, valley fog and long shadows.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 7:45 AM | 8:17 AM | 9:02 AM | 4:48 PM | 5:33 PM | 6:05 PM | 9h 17m |
| February | 7:15 AM | 7:45 AM | 8:25 AM | 5:35 PM | 6:15 PM | 6:45 PM | 10h 30m |
| March | 7:29 AM | 7:58 AM | 8:36 AM | 7:13 PM | 7:51 PM | 8:20 PM | 11h 53m |
| April | 6:33 AM | 7:03 AM | 7:41 AM | 7:50 PM | 8:29 PM | 8:59 PM | 13h 26m |
| May | 5:47 AM | 6:20 AM | 7:02 AM | 8:23 PM | 9:04 PM | 9:38 PM | 14h 44m |
| June | 5:27 AM | 6:03 AM | 6:47 AM | 8:46 PM | 9:30 PM | 10:06 PM | 15h 27m |
| July | 5:42 AM | 6:17 AM | 7:00 AM | 8:43 PM | 9:26 PM | 10:01 PM | 15h 09m |
| August | 6:19 AM | 6:50 AM | 7:30 AM | 8:11 PM | 8:51 PM | 9:22 PM | 14h 01m |
| September | 6:56 AM | 7:25 AM | 8:03 AM | 7:19 PM | 7:57 PM | 8:26 PM | 12h 32m |
| October | 7:31 AM | 8:00 AM | 8:39 AM | 6:24 PM | 7:03 PM | 7:32 PM | 11h 03m |
| November | 7:09 AM | 7:40 AM | 8:24 AM | 4:37 PM | 5:21 PM | 5:52 PM | 9h 40m |
| December | 7:40 AM | 8:13 AM | 9:00 AM | 4:22 PM | 5:09 PM | 5:42 PM | 8h 56m |
Local time (America/Boise), 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 Spring Valley Summit, the Milky Way core is visible in a dark sky from March through September. June gives the longest window (about 3.7 hours on a moonless night), and the core peaks around 17° above the southern horizon. Our light-pollution model puts the sky at about Bortle 4 (rural / suburban transition), good enough for detailed Milky Way images.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | -4° | — |
| February | Below 10° in darkness | — | 8° | — |
| March | 5:37 AM – 6:17 AM | 0.7 | 14° | SSE → SSE |
| April | 3:33 AM – 5:13 AM | 1.7 | 17° | SSE → S |
| May | 1:37 AM – 4:07 AM | 2.5 | 17° | SSE → S |
| June | 11:52 PM – 3:32 AM | 3.7 | 17° | SSE → SSW |
| July | 11:39 PM – 2:19 AM | 2.7 | 17° | S → SSW |
| August | 10:42 PM – 12:12 AM | 1.5 | 16° | S → SSW |
| September | 9:35 PM – 10:15 PM | 0.7 | 14° | SSW → SSW |
| October | Below 10° in darkness | — | 8° | — |
| November | Below 10° in darkness | — | -2° | — |
| December | Below 10° in darkness | — | -20° | — |
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: 4 Bortle 4 — Rural / suburban transition. Light domes are visible in several directions; the Milky Way is clear but lacks detail near the horizon. Modeled zenith brightness ≈ 20.89 mag/arcsec². Aurora needs roughly Kp 6.0+ to show low on the northern horizon here.
Weather & best season
Long-term NASA satellite data for this area show July as the clearest month (about 26% average cloud cover) and December as the cloudiest (73%). 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 | 57 | 60 | 74 | 87 | 100 | 108 | 110 | 108 | 101 | 92 | 73 | 58 |
| Low °F | -9 | 8 | 16 | 23 | 27 | 36 | 46 | 45 | 34 | 18 | 6 | -5 |
| Precip. (in) | 1.9 | 1.6 | 1.8 | 1.4 | 1.4 | 1.0 | 0.2 | 0.2 | 0.6 | 1.1 | 1.6 | 2.5 |
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 pass
- Weather changes fast at elevation; carry layers even in summer.
- Summit pull-outs often face one direction; use the sun azimuth table to see whether sunrise or sunset suits the view.
- Wildflowers bloom late at pass elevations — often July to early August in the Rockies and Sierra.
- Check road status before driving: many high passes close seasonally or after storms.
- Look for the road itself as a leading line — switchbacks from above make strong compositions.
- Check road and trail conditions with the managing agency before you go.
Season: Summer and early autumn are the main season; winter visits depend on plowing and avalanche conditions.
Suggested gear: Telephoto lens, Tripod, Warm layers, Road-condition app. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Nearby photo spots
Other locations within 25 km of Spring Valley Summit, closest first.
Campgrounds nearby (Recreation.gov)
FAQ
When is the best time to photograph Spring Valley Summit?
What time is golden hour at Spring Valley Summit?
Where does the sun rise and set at Spring Valley Summit?
Can you see the Milky Way from Spring Valley Summit?
Do you need a permit to photograph at Spring Valley Summit?
How far is Spring Valley Summit from Hidden Spring?
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.