Located in Fremont County, Wyoming, Boysen State Park is a state park. The nearest town is Thermopolis, about 26 km (16 mi) away (Boysen State Park lies S of town).
Boysen State Park is a public recreation area surrounding the Boysen Reservoir, an impoundment of the north-flowing Wind River, in Fremont County, Wyoming. The state park covers more than 35,000 acres (14,000 ha) at the south end of the Owl Creek Mountains at the mouth of the Wind River Canyon.From the Wikipedia article “Boysen State Park”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Boysen State Park the sunrise point swings a long way through the year: about 56° (NE) 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 70° in summer but only 23° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 7:17 AM | 90° E | 7:25 PM | 271° W | 46° | 12h 08m |
| June solstice (Jun 21) | 5:33 AM | 56° NE | 8:58 PM | 304° NW | 70° | 15h 25m |
| September equinox (Sep 22) | 7:01 AM | 89° E | 7:12 PM | 271° W | 47° | 12h 11m |
| December solstice (Dec 21) | 7:43 AM | 122° ESE | 4:40 PM | 238° WSW | 23° | 8h 57m |
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 | 7:11 AM | 7:43 AM | 8:28 AM | 4:18 PM | 5:02 PM | 5:34 PM | 9h 19m |
| February | 6:43 AM | 7:12 AM | 7:52 AM | 5:04 PM | 5:44 PM | 6:13 PM | 10h 32m |
| March | 6:57 AM | 7:26 AM | 8:04 AM | 6:41 PM | 7:19 PM | 7:48 PM | 11h 53m |
| April | 6:01 AM | 6:31 AM | 7:09 AM | 7:17 PM | 7:56 PM | 8:26 PM | 13h 25m |
| May | 5:16 AM | 5:49 AM | 6:30 AM | 7:50 PM | 8:31 PM | 9:04 PM | 14h 42m |
| June | 4:57 AM | 5:32 AM | 6:16 AM | 8:12 PM | 8:56 PM | 9:32 PM | 15h 24m |
| July | 5:12 AM | 5:46 AM | 6:29 AM | 8:10 PM | 8:52 PM | 9:27 PM | 15h 06m |
| August | 5:48 AM | 6:19 AM | 6:58 AM | 7:38 PM | 8:18 PM | 8:49 PM | 13h 59m |
| September | 6:24 AM | 6:53 AM | 7:31 AM | 6:47 PM | 7:25 PM | 7:53 PM | 12h 32m |
| October | 6:58 AM | 7:27 AM | 8:06 AM | 5:52 PM | 6:31 PM | 7:00 PM | 11h 04m |
| November | 6:36 AM | 7:07 AM | 7:50 AM | 4:06 PM | 4:49 PM | 5:20 PM | 9h 42m |
| December | 7:07 AM | 7:39 AM | 8:26 AM | 3:52 PM | 4:38 PM | 5:11 PM | 8h 59m |
Local time (America/Denver), 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 Boysen State Park, the Milky Way core is visible in a dark sky from March through September. June gives the longest window (about 3.8 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 1 (excellent dark-sky site), which is excellent for astrophotography.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | -4° | — |
| February | Below 10° in darkness | — | 8° | — |
| March | 5:05 AM – 5:45 AM | 0.7 | 14° | SSE → SSE |
| April | 3:00 AM – 4:40 AM | 1.7 | 17° | SSE → S |
| May | 1:04 AM – 3:44 AM | 2.7 | 18° | SSE → S |
| June | 11:18 PM – 3:08 AM | 3.8 | 18° | SSE → SSW |
| July | 11:05 PM – 1:45 AM | 2.7 | 18° | S → SSW |
| August | 10:08 PM – 11:48 PM | 1.7 | 17° | S → SSW |
| September | 9:03 PM – 9:43 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: 1 Bortle 1 — Excellent dark-sky site. The Milky Way casts faint shadows; zodiacal light and airglow are obvious. Modeled zenith brightness ≈ 21.92 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 38% average cloud cover) and December as the cloudiest (69%). 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 | 57 | 56 | 68 | 79 | 90 | 94 | 99 | 96 | 94 | 81 | 70 | 52 |
| Low °F | -15 | -15 | -3 | 7 | 17 | 28 | 39 | 37 | 21 | 2 | -8 | -14 |
| Precip. (in) | 0.6 | 0.8 | 1.1 | 1.8 | 2.6 | 1.4 | 1.0 | 0.8 | 1.3 | 1.2 | 0.8 | 0.7 |
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 Boysen State Park, closest first.
FAQ
When is the best time to photograph Boysen State Park?
What time is golden hour at Boysen State Park?
Where does the sun rise and set at Boysen State Park?
Can you see the Milky Way from Boysen State Park?
Do you need a permit to photograph at Boysen State Park?
How far is Boysen State Park from Thermopolis?
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.