Castle Geyser is a hot spring in Teton County, Wyoming. It lies in or next to Yellowstone National Park, so park hours, fees and rules apply. It sits roughly 31 km (19 mi) SE of West Yellowstone.
Castle Geyser is a cone geyser in the Upper Geyser Basin of Yellowstone National Park. It is noted for the particularly large geyserite sinter deposits, which form its cone. These deposits have been likened in appearance to a castle. When the geyser was given this name in 1870, the top edges of the structure resembled the typical profile associated with the modern concept of a castle, having the appearance of a large keep, multiple turrets, and especially because of the crenellation along the top edges of what resembled its towers. As the drawing below shows the cone had distinctive appearance at the time. Over time the cone's shape changes because of the layers of mineral deposited in successive eruptions.From the Wikipedia article “Castle Geyser”, licensed under CC BY-SA 4.0.
From the National Park Service
The cone of Castle Geyser is thousands of years old and rests upon even older platforms. Together, they form one of the largest sinter formations in the world. Castle currently erupts, on average, every 14 hours. ##View all geyser predictions The water eruption frequently reaches 75 feet (24 m) and lasts about 20 minutes, followed by a noisy steam phase of 30-40 minutes. If Castle has a minor eruption (a few minutes of water but no steam), its next major eruption cannot be predicted. Castle Geyser has a unique, large, tall geyserite cone structure that may be reminiscent of a castle. This large structure is possibly due to trees growing in the area years prior that became coated in sinter and allowed the height to build up. Layers of geyserite cascade in step-like terraces from the geyser vent and continues to cover the surrounding area. Due to this amount of fragile sinter and the height of the cone, the water is inaccessible for scientific measurements. The western side of Castle Geyser appears smoother than the sinter steps on the east side. As the story goes, thermophile mats use to live on the cone but were peeled off by visitors, permanently damaging the cone structure. Now the water flows down the east side and no thermophiles are visible. Geysers Geysers have constrictions in their plumbing systems that prevent water from moving freely to the surface where heat would escape. Water beneath the constrictions creates a buildup of steam. Eventually the steam pushes water past the constrictions and the geyser erupts. Upper Geyser Basin The majority of world’s active geysers are in the Upper Geyser Basin, including Old Faithful. Only four other places in the world have large concentrations of hydrothermal features: Russia (Kamchatka), Chile, New Zealand, and Iceland. The heat for the hydrothermal features comes from Yellowstone’s volcano. Molten rock or magma may be as close as 3-8 miles (5-13 km) underground. Rain and snow supply water that seeps down several thousand feet (more than a kilometer) below the surface where it is heated. Underground cracks form a natural plumbing system. Hot water rises through the plumbing to produce hot springs and geysers. Use Caution in Hydrothermal Areas Stay on boardwalks and designated trails. Hydrothermal water can severely burn you. Never run, push, or shove. Supervise children at all times. Do not scra
Text: National Park Service (public domain) — nps.gov.
Sunrise & sunset directions
At Castle Geyser the sunrise point swings a long way through the year: about 55° (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 | 45° | 12h 09m |
| June solstice (Jun 21) | 5:40 AM | 55° NE | 9:12 PM | 305° NW | 69° | 15h 33m |
| 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 | 4:47 PM | 237° WSW | 22° | 8h 50m |
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
Steam is most visible on cold mornings; backlight from a low sun makes rising steam glow.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 7:25 AM | 7:57 AM | 8:43 AM | 4:24 PM | 5:10 PM | 5:42 PM | 9h 13m |
| February | 6:54 AM | 7:24 AM | 8:05 AM | 5:12 PM | 5:53 PM | 6:22 PM | 10h 28m |
| March | 7:08 AM | 7:37 AM | 8:15 AM | 6:51 PM | 7:30 PM | 7:59 PM | 11h 53m |
| April | 6:10 AM | 6:40 AM | 7:19 AM | 7:29 PM | 8:08 PM | 8:38 PM | 13h 28m |
| May | 5:23 AM | 5:57 AM | 6:39 AM | 8:02 PM | 8:44 PM | 9:18 PM | 14h 48m |
| June | 5:02 AM | 5:39 AM | 6:24 AM | 8:26 PM | 9:10 PM | 9:47 PM | 15h 31m |
| July | 5:18 AM | 5:53 AM | 6:37 AM | 8:23 PM | 9:06 PM | 9:42 PM | 15h 13m |
| August | 5:56 AM | 6:27 AM | 7:07 AM | 7:50 PM | 8:30 PM | 9:02 PM | 14h 03m |
| September | 6:34 AM | 7:03 AM | 7:41 AM | 6:58 PM | 7:36 PM | 8:05 PM | 12h 33m |
| October | 7:10 AM | 7:39 AM | 8:19 AM | 6:01 PM | 6:41 PM | 7:10 PM | 11h 02m |
| November | 6:49 AM | 7:20 AM | 8:04 AM | 4:13 PM | 4:57 PM | 5:29 PM | 9h 37m |
| December | 7:20 AM | 7:54 AM | 8:42 AM | 3:57 PM | 4:45 PM | 5:18 PM | 8h 51m |
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 Castle Geyser, 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 | — | -3° | — |
| February | Below 10° in darkness | — | 8° | — |
| March | 5:17 AM – 5:57 AM | 0.7 | 13° | SSE → SSE |
| April | 3:14 AM – 4:44 AM | 1.5 | 16° | SSE → S |
| May | 1:21 AM – 3:41 AM | 2.3 | 17° | SSE → S |
| June | 11:39 PM – 3:09 AM | 3.5 | 17° | SSE → SSW |
| July | 11:24 PM – 1:44 AM | 2.3 | 17° | S → SSW |
| August | 10:23 PM – 11:43 PM | 1.3 | 16° | SSW → SSW |
| September | 9:15 PM – 9:45 PM | 0.5 | 13° | SSW → SSW |
| October | Below 10° in darkness | — | 7° | — |
| 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 hot spring
- Respect bathers' privacy: ask before including people at soaking pools.
- Wind direction determines where steam drifts; shoot from the upwind side to see the pool.
- Condensation forms quickly on lenses; let gear acclimate and carry a cloth.
- Keep to boardwalks and marked paths — crusts around thermal features can be thin and the water dangerously hot.
- Check road and trail conditions with the managing agency before you go.
Season: Winter gives the most dramatic steam; some primitive springs are only accessible in summer.
Suggested gear: Circular polarizer, Lens cloth, Telephoto for distant pools. 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 Castle Geyser, closest first.
Hot Spring
Hot Spring
Hot Spring
Hot Spring
Hot Spring
Hot Spring
Hot Spring
Hot Spring
Hot SpringCampgrounds nearby (Recreation.gov)
FAQ
When is the best time to photograph Castle Geyser?
What time is golden hour at Castle Geyser?
Where does the sun rise and set at Castle Geyser?
Can you see the Milky Way from Castle Geyser?
Do you need a permit to photograph at Castle Geyser?
How far is Castle Geyser from West Yellowstone?
Sources
Location data: Wikidata, National Park Service, 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.