Decorah Ice Cave State Preserve — a cave in Winneshiek County, Iowa — is a classic subject for landscape photographers. The nearest town is Decorah, about 800 m away (Decorah Ice Cave State Preserve lies N of town). It is listed on the National Register of Historic Places.
Decorah Ice Cave State Preserve has one of the largest ice caves in the Midwestern United States. It consists of a 3-acre (1.2 ha) parcel of land at the edge of Barbara Barnhart VanPeenen Memorial Park in the northern portion of the city of Decorah, in Winneshiek County, Iowa. Ice Cave is open to the public as an 'enter at your own risk' attraction. In the late 1990s, the Department of Natural Resources Geological Survey Bureau required a permanent barrier be installed due to some rock movement. Since then, a large rock has fallen and visitors are now only able to comfortably walk into the cave about 10 feet from the entrance. Ice caves are one characteristic of karst topography, along with sinkholes and cave systems, all of which are present in the area, a portion of the Driftless Area of Iowa. From autumn and into early winter the cave is dry. Ice begins to form in January or...From the Wikipedia article “Decorah Ice Cave State Preserve”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Decorah Ice Cave State Preserve 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) | 7:11 AM | 90° E | 7:20 PM | 271° W | 47° | 12h 08m |
| June solstice (Jun 21) | 5:28 AM | 56° NE | 8:52 PM | 304° NW | 70° | 15h 24m |
| September equinox (Sep 22) | 6:55 AM | 89° E | 7:06 PM | 271° W | 47° | 12h 11m |
| December solstice (Dec 21) | 7:37 AM | 122° ESE | 4:35 PM | 238° WSW | 23° | 8h 58m |
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
Caves are lit artificially — show caves have fixed lighting, so a fast lens and high ISO beat flash, which flattens formations.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 7:06 AM | 7:37 AM | 8:22 AM | 4:12 PM | 4:57 PM | 5:29 PM | 9h 20m |
| February | 6:37 AM | 7:06 AM | 7:46 AM | 4:58 PM | 5:38 PM | 6:07 PM | 10h 32m |
| March | 6:52 AM | 7:20 AM | 7:58 AM | 6:36 PM | 7:14 PM | 7:42 PM | 11h 53m |
| April | 5:56 AM | 6:26 AM | 7:04 AM | 7:12 PM | 7:50 PM | 8:20 PM | 13h 24m |
| May | 5:11 AM | 5:44 AM | 6:25 AM | 7:44 PM | 8:25 PM | 8:58 PM | 14h 41m |
| June | 4:51 AM | 5:27 AM | 6:11 AM | 8:06 PM | 8:50 PM | 9:25 PM | 15h 23m |
| July | 5:07 AM | 5:41 AM | 6:24 AM | 8:04 PM | 8:46 PM | 9:21 PM | 15h 05m |
| August | 5:42 AM | 6:13 AM | 6:52 AM | 7:33 PM | 8:12 PM | 8:43 PM | 13h 59m |
| September | 6:19 AM | 6:47 AM | 7:25 AM | 6:42 PM | 7:19 PM | 7:48 PM | 12h 32m |
| October | 6:53 AM | 7:21 AM | 8:00 AM | 5:47 PM | 6:26 PM | 6:54 PM | 11h 04m |
| November | 6:30 AM | 7:01 AM | 7:44 AM | 4:01 PM | 4:44 PM | 5:15 PM | 9h 43m |
| December | 7:01 AM | 7:33 AM | 8:20 AM | 3:46 PM | 4:33 PM | 5:05 PM | 9h 00m |
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 Decorah Ice Cave State Preserve, 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 5 (suburban sky), so expect visible sky glow; drive away from towns for better results.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | -4° | — |
| February | Below 10° in darkness | — | 9° | — |
| March | 4:49 AM – 5:39 AM | 0.8 | 14° | SSE → SSE |
| April | 2:53 AM – 4:33 AM | 1.7 | 17° | SSE → S |
| May | 12:56 AM – 3:36 AM | 2.7 | 18° | SSE → S |
| June | 11:09 PM – 2:59 AM | 3.8 | 18° | SSE → SSW |
| July | 10:57 PM – 1:47 AM | 2.8 | 18° | S → SSW |
| August | 10:01 PM – 11:41 PM | 1.7 | 17° | S → SSW |
| September | 8:56 PM – 9:36 PM | 0.7 | 14° | 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: 5 Bortle 5 — Suburban sky. The Milky Way is weak near the horizon and washed out overhead; long exposures pick up a sky glow. Modeled zenith brightness ≈ 20.07 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 47% average cloud cover) and December as the cloudiest (71%). 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 | 49 | 63 | 77 | 82 | 91 | 97 | 105 | 100 | 94 | 83 | 71 | 65 |
| Low °F | -39 | -21 | -20 | 10 | 27 | 39 | 47 | 41 | 32 | 22 | 2 | -27 |
| Precip. (in) | 1.1 | 1.3 | 2.0 | 3.8 | 4.7 | 5.7 | 4.1 | 4.2 | 4.1 | 2.9 | 1.8 | 1.7 |
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 cave
- Many show caves restrict tripods on tours; ask in advance or bring a small beanbag.
- Use manual focus with focus peaking in low light.
- Never touch formations — skin oils stop their growth.
- Follow White-nose Syndrome decontamination rules where posted to protect bats.
- Tell someone where you're going in remote areas and carry the ten essentials.
Season: Cave interiors stay at a constant temperature year-round; summer tours fill up, so book ahead.
Suggested gear: Fast lens (f/1.8–f/2.8), High-ISO camera, Small beanbag. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Nearby photo spots
Other locations within 25 km of Decorah Ice Cave State Preserve, closest first.
FAQ
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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.