Located in Clay County, South Dakota, Spirit Mound Historic Prairie is a state park. The nearest town is Vermillion, about 10.8 km (6.7 mi) away (Spirit Mound Historic Prairie lies NNW of town).
Spirit Mound Historic Prairie is a state park in Clay County, South Dakota, United States, featuring a prominent hill on the Great Plains. The Plains Indians of the region considered Spirit Mound the home of dangerous spirits or little people; members of the Lewis and Clark Expedition climbed it on August 25, 1804. The park was established in 2002. It is located about 6.5 miles (10.5 km) north of Vermillion, South Dakota.From the Wikipedia article “Spirit Mound Historic Prairie”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Spirit Mound Historic Prairie the sunrise point swings a long way through the year: about 56° (ENE) at the June solstice and 122° (ESE) in late December. Sunset moves from 304° (NW) in June to 238° (WSW) in December, and the midday sun climbs to 71° in summer but only 24° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 7:32 AM | 90° E | 7:40 PM | 271° W | 47° | 12h 08m |
| June solstice (Jun 21) | 5:50 AM | 56° ENE | 9:11 PM | 304° NW | 71° | 15h 21m |
| September equinox (Sep 22) | 7:16 AM | 89° E | 7:27 PM | 271° W | 47° | 12h 11m |
| December solstice (Dec 21) | 7:56 AM | 122° ESE | 4:57 PM | 238° WSW | 24° | 9h 01m |
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
State parks often protect a signature feature — a gorge, lake or overlook — that is best in early morning before visitors and harsh light arrive.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 7:25 AM | 7:57 AM | 8:41 AM | 4:35 PM | 5:19 PM | 5:50 PM | 9h 22m |
| February | 6:57 AM | 7:26 AM | 8:06 AM | 5:20 PM | 6:00 PM | 6:29 PM | 10h 33m |
| March | 7:13 AM | 7:41 AM | 8:18 AM | 6:57 PM | 7:34 PM | 8:03 PM | 11h 54m |
| April | 6:17 AM | 6:47 AM | 7:25 AM | 7:32 PM | 8:10 PM | 8:40 PM | 13h 23m |
| May | 5:33 AM | 6:06 AM | 6:47 AM | 8:04 PM | 8:44 PM | 9:17 PM | 14h 38m |
| June | 5:14 AM | 5:49 AM | 6:33 AM | 8:26 PM | 9:09 PM | 9:44 PM | 15h 20m |
| July | 5:29 AM | 6:03 AM | 6:45 AM | 8:23 PM | 9:05 PM | 9:39 PM | 15h 02m |
| August | 6:04 AM | 6:35 AM | 7:14 AM | 7:53 PM | 8:32 PM | 9:02 PM | 13h 57m |
| September | 6:40 AM | 7:08 AM | 7:46 AM | 7:02 PM | 7:40 PM | 8:08 PM | 12h 31m |
| October | 7:13 AM | 7:42 AM | 8:20 AM | 6:08 PM | 6:47 PM | 7:15 PM | 11h 05m |
| November | 6:50 AM | 7:21 AM | 8:03 AM | 4:24 PM | 5:06 PM | 5:36 PM | 9h 45m |
| December | 7:20 AM | 7:53 AM | 8:39 AM | 4:09 PM | 4:55 PM | 5:27 PM | 9h 02m |
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 Spirit Mound Historic Prairie, the Milky Way core is visible in a dark sky from March through September. June gives the longest window (about 4.0 hours on a moonless night), and the core peaks around 18° 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 | — | -4° | — |
| February | Below 10° in darkness | — | 9° | — |
| March | 5:09 AM – 5:59 AM | 0.8 | 15° | SSE → SSE |
| April | 3:12 AM – 5:02 AM | 1.8 | 18° | SSE → S |
| May | 1:14 AM – 4:04 AM | 2.8 | 18° | SSE → S |
| June | 11:25 PM – 3:25 AM | 4.0 | 18° | SSE → SSW |
| July | 11:14 PM – 2:04 AM | 2.8 | 18° | S → SSW |
| August | 10:20 PM – 12:10 AM | 1.8 | 18° | S → SSW |
| September | 9:16 PM – 10:06 PM | 0.8 | 15° | SSW → SSW |
| October | Below 10° in darkness | — | 9° | — |
| 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 ≈ 21.58 mag/arcsec². Aurora needs roughly Kp 5.5+ to show low on the northern horizon here.
Weather & best season
Long-term NASA satellite data for this area show September as the clearest month (about 44% average cloud cover) and December as the cloudiest (65%). 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 | 55 | 69 | 86 | 89 | 95 | 106 | 111 | 107 | 100 | 91 | 77 | 58 |
| Low °F | -31 | -18 | -10 | 12 | 24 | 44 | 49 | 46 | 36 | 13 | 5 | -16 |
| Precip. (in) | 0.6 | 1.0 | 1.6 | 3.1 | 4.1 | 4.5 | 3.1 | 3.6 | 3.4 | 2.3 | 1.2 | 1.1 |
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 state park
- Check park hours: many state parks close at dusk, which affects sunset and night shooting.
- Ask rangers about photography permits for commercial work, models or drones.
- Weekday mornings are the least crowded at popular viewpoints.
- Trail maps often mark overlooks — combine them with the sun azimuth to plan.
- Scout in daylight if you plan to shoot at night or before sunrise.
Season: Spring wildflowers and autumn color are peak seasons in most parks.
Suggested gear: Versatile zoom lens, Tripod, Park pass. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Permits, drones & access
Drones: Drone rules in state parks vary by state and even by park — many require a permit or ban recreational drone flights. Check the park's rules and the FAA B4UFLY app before flying.
Nearby photo spots
Other locations within 40 km of Spirit Mound Historic Prairie, closest first.
Campgrounds nearby (Recreation.gov)
FAQ
When is the best time to photograph Spirit Mound Historic Prairie?
What time is golden hour at Spirit Mound Historic Prairie?
Where does the sun rise and set at Spirit Mound Historic Prairie?
Can you see the Milky Way from Spirit Mound Historic Prairie?
Do you need a permit to photograph at Spirit Mound Historic Prairie?
How far is Spirit Mound Historic Prairie from Vermillion?
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.