Union Falls — a waterfall in Teton County, Wyoming at about 2,070 m (6,791 ft) above sea level — is a rewarding subject for landscape photographers. It lies in or next to Yellowstone National Park, so park hours, fees and rules apply. It sits roughly 48 km (30 mi) ENE of Ashton.
Union Falls is a fan-type waterfall on Mountain Ash Creek, a tributary of the Fall River in the Cascade Corner (southwest) of Yellowstone National Park, in Wyoming, United States. With a height of 250 feet (76 m), it is the second tallest major waterfall in Yellowstone, exceeded only by the lower Yellowstone Falls. The falls was named by members of the Arnold Hague Geological Surveys sometime between 1884 and 1886. Geologist J.P. Iddings claims the name derives from the fact that a tributary of Mountain Ash Creek joins at the very brink of the falls, thus Union Falls. Access to the falls is via the Mountain Ash Creek trail and the Grassy Lake Road.From the Wikipedia article “Union Falls”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Union Falls 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 237° (WSW) in December, and the midday sun climbs to 69° in summer but only 22° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 7:27 AM | 90° E | 7:36 PM | 271° W | 46° | 12h 09m |
| June solstice (Jun 21) | 5:41 AM | 56° NE | 9:11 PM | 305° NW | 69° | 15h 31m |
| September equinox (Sep 22) | 7:11 AM | 89° E | 7:23 PM | 271° W | 46° | 12h 11m |
| December solstice (Dec 21) | 7:57 AM | 123° ESE | 4:48 PM | 237° WSW | 22° | 8h 52m |
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
Waterfalls photograph best in soft, even light: overcast days, deep shade, or the hour after sunrise before direct sun hits the water. Bright sun on white water blows highlights and adds harsh contrast.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 7:24 AM | 7:56 AM | 8:42 AM | 4:25 PM | 5:11 PM | 5:43 PM | 9h 15m |
| February | 6:54 AM | 7:24 AM | 8:05 AM | 5:12 PM | 5:53 PM | 6:23 PM | 10h 29m |
| March | 7:08 AM | 7:37 AM | 8:15 AM | 6:52 PM | 7:30 PM | 7:59 PM | 11h 53m |
| April | 6:10 AM | 6:41 AM | 7:19 AM | 7:29 PM | 8:08 PM | 8:38 PM | 13h 27m |
| May | 5:24 AM | 5:58 AM | 6:40 AM | 8:02 PM | 8:44 PM | 9:17 PM | 14h 46m |
| June | 5:04 AM | 5:40 AM | 6:24 AM | 8:25 PM | 9:10 PM | 9:46 PM | 15h 29m |
| July | 5:19 AM | 5:55 AM | 6:38 AM | 8:22 PM | 9:06 PM | 9:41 PM | 15h 11m |
| August | 5:56 AM | 6:28 AM | 7:08 AM | 7:50 PM | 8:30 PM | 9:01 PM | 14h 02m |
| September | 6:34 AM | 7:03 AM | 7:42 AM | 6:58 PM | 7:36 PM | 8:05 PM | 12h 32m |
| October | 7:10 AM | 7:39 AM | 8:18 AM | 6:02 PM | 6:41 PM | 7:10 PM | 11h 02m |
| November | 6:49 AM | 7:20 AM | 8:04 AM | 4:14 PM | 4:58 PM | 5:29 PM | 9h 38m |
| December | 7:20 AM | 7:53 AM | 8:40 AM | 3:59 PM | 4:46 PM | 5:19 PM | 8h 53m |
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 Union Falls, the Milky Way core is visible in a dark sky from March through September. June gives the longest window (about 3.5 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 1 (excellent dark-sky site), which is excellent for astrophotography.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | -5° | — |
| February | Below 10° in darkness | — | 8° | — |
| March | 5:16 AM – 5:56 AM | 0.7 | 13° | SSE → SSE |
| April | 3:13 AM – 4:43 AM | 1.5 | 16° | SSE → S |
| May | 1:19 AM – 3:49 AM | 2.5 | 17° | SSE → S |
| June | 11:36 PM – 3:06 AM | 3.5 | 17° | SSE → SSW |
| July | 11:21 PM – 1:51 AM | 2.5 | 17° | S → SSW |
| August | 10:22 PM – 11:52 PM | 1.5 | 16° | S → SSW |
| September | 9:15 PM – 9:45 PM | 0.5 | 13° | SSW → SSW |
| October | Below 10° in darkness | — | 8° | — |
| November | Below 10° in darkness | — | -3° | — |
| 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 ≈ 21.93 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 July as the clearest month (about 39% average cloud cover) and February as the cloudiest (77%). 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 | 33 | 32 | 51 | 64 | 73 | 80 | 90 | 90 | 82 | 72 | 53 | 33 |
| Low °F | -32 | -34 | -21 | -10 | 6 | 22 | 29 | 28 | 18 | -9 | -23 | -32 |
| Precip. (in) | 3.1 | 3.1 | 3.0 | 3.2 | 3.1 | 2.8 | 1.4 | 1.6 | 2.0 | 2.6 | 3.1 | 3.5 |
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 waterfall
- A circular polarizer cuts glare on wet rocks and leaves and deepens greens — rotate it while watching the rocks, not the sky.
- Spring snowmelt and the days after heavy rain give the strongest flow; late summer flow can drop to a trickle.
- Look for a foreground: a mossy boulder, a fallen log or the creek's leading lines make a stronger frame than the falls alone.
- Keep a microfiber cloth handy — spray drifts onto the lens, especially at the plunge pool.
- Bracket shutter speeds: 1/8 s, 1/2 s and 2 s give very different water textures and you can choose later.
- Check road and trail conditions with the managing agency before you go.
Season: Peak flow is usually in late spring; autumn adds color around the falls, and winter can bring ice formations at colder locations.
Suggested gear: Tripod, Circular polarizer, 3–6 stop ND filter, Lens cloth, Waterproof footwear. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Permits, drones & access
National Park Service rules. Under federal law (54 U.S.C. 100905), still photography in National Park Service areas needs a permit only when it (1) takes place where members of the public are not allowed, (2) uses models, sets or props that are not part of the location's natural or cultural resources or administrative facilities, or (3) would cause the park to incur additional administrative costs to monitor the activity. Ordinary visitor and most landscape photography needs no permit. Commercial filming rules are separate and have changed in recent years — confirm current requirements with the park before a paid shoot.
Drones: Launching, landing or operating unmanned aircraft (drones) is prohibited in National Park Service units under a 2014 Superintendent's closure (36 CFR 1.5), except where a park has issued specific written approval. Flying from outside the boundary over park land can also violate park rules and disturb wildlife.
Nearby photo spots
Other locations within 25 km of Union Falls, closest first.
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WaterfallWaterfallWaterfallWaterfallWaterfallCampgrounds nearby (Recreation.gov)
- Cave Falls Campground13.5 km (8.4 mi)
- Squirrel Meadows Cabin18.8 km (11.7 mi) · reservable
- Headwaters Campground At Flagg Ranch18.9 km (11.8 mi) · reservable
- Lewis Lake Campground22 km (14 mi) · reservable
- Lizard Creek Campground26 km (16 mi) · reservable
FAQ
When is the best time to photograph Union Falls?
What time is golden hour at Union Falls?
Where does the sun rise and set at Union Falls?
Can you see the Milky Way from Union Falls?
Do you need a permit to photograph at Union Falls?
How far is Union Falls from Ashton?
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.