Tyson Spring Cave is a cave in Fillmore County, Minnesota. The nearest town is Chatfield, about 10.5 km (6.5 mi) away (Tyson Spring Cave lies SSW of town).
Tyson Spring Cave is a cave located in southeastern Minnesota's Fillmore County. The region is within the Driftless Area, a region noted for its karst topography, which includes caves and sinkholes. Tyson's cave is a solutional cave privately owned by the Minnesota Cave Preserve. It is known for the extinct ice-age bones found scattered throughout the cave rooms. The majority of this extensive cave is approximately 120 feet below the surface and is estimated to be 3.5–5 miles in length, making it the 258th longest cave in the United States.From the Wikipedia article “Tyson Spring Cave”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Tyson Spring Cave 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 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) | 7:13 AM | 90° E | 7:21 PM | 271° W | 46° | 12h 08m |
| June solstice (Jun 21) | 5:28 AM | 56° NE | 8:55 PM | 305° NW | 70° | 15h 27m |
| September equinox (Sep 22) | 6:57 AM | 89° E | 7:08 PM | 271° W | 47° | 12h 11m |
| December solstice (Dec 21) | 7:40 AM | 123° ESE | 4:35 PM | 238° WSW | 23° | 8h 55m |
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 | 7:08 AM | 7:40 AM | 8:26 AM | 4:12 PM | 4:57 PM | 5:29 PM | 9h 17m |
| February | 6:39 AM | 7:09 AM | 7:49 AM | 4:59 PM | 5:39 PM | 6:09 PM | 10h 30m |
| March | 6:53 AM | 7:22 AM | 8:00 AM | 6:37 PM | 7:15 PM | 7:44 PM | 11h 53m |
| April | 5:57 AM | 6:27 AM | 7:05 AM | 7:14 PM | 7:52 PM | 8:22 PM | 13h 26m |
| May | 5:11 AM | 5:44 AM | 6:26 AM | 7:46 PM | 8:28 PM | 9:01 PM | 14h 43m |
| June | 4:51 AM | 5:27 AM | 6:11 AM | 8:09 PM | 8:53 PM | 9:29 PM | 15h 26m |
| July | 5:07 AM | 5:41 AM | 6:24 AM | 8:07 PM | 8:50 PM | 9:24 PM | 15h 08m |
| August | 5:43 AM | 6:14 AM | 6:54 AM | 7:35 PM | 8:15 PM | 8:46 PM | 14h 00m |
| September | 6:20 AM | 6:49 AM | 7:27 AM | 6:43 PM | 7:21 PM | 7:50 PM | 12h 32m |
| October | 6:55 AM | 7:24 AM | 8:03 AM | 5:48 PM | 6:27 PM | 6:56 PM | 11h 03m |
| November | 6:33 AM | 7:04 AM | 7:47 AM | 4:01 PM | 4:45 PM | 5:16 PM | 9h 41m |
| December | 7:04 AM | 7:37 AM | 8:24 AM | 3:46 PM | 4:33 PM | 5:06 PM | 8h 56m |
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 Tyson Spring Cave, the Milky Way core is visible in a dark sky from March through September. June gives the longest window (about 3.7 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 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 | — | 8° | — |
| March | 5:01 AM – 5:41 AM | 0.7 | 14° | SSE → SSE |
| April | 2:57 AM – 4:37 AM | 1.7 | 17° | SSE → S |
| May | 1:01 AM – 3:31 AM | 2.5 | 17° | SSE → S |
| June | 11:16 PM – 2:56 AM | 3.7 | 17° | SSE → SSW |
| July | 11:03 PM – 1:43 AM | 2.7 | 17° | S → SSW |
| August | 10:06 PM – 11:36 PM | 1.5 | 16° | S → SSW |
| September | 8:59 PM – 9:39 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: 3 Bortle 3 — Rural sky. Some light domes sit on the horizon, but the Milky Way still looks complex overhead. Modeled zenith brightness ≈ 21.52 mag/arcsec². Aurora needs roughly Kp 5.0+ 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 (70%). 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 | 61 | 77 | 83 | 92 | 96 | 102 | 99 | 92 | 82 | 73 | 63 |
| Low °F | -35 | -21 | -20 | 9 | 25 | 39 | 46 | 41 | 31 | 19 | 0 | -28 |
| Precip. (in) | 1.0 | 1.3 | 1.9 | 3.7 | 4.7 | 5.7 | 3.9 | 4.1 | 4.1 | 2.9 | 1.7 | 1.6 |
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
- 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.
- Many show caves restrict tripods on tours; ask in advance or bring a small beanbag.
- Bring a spare battery — cold weather and long exposures drain them fast.
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 Tyson Spring Cave, closest first.
FAQ
When is the best time to photograph Tyson Spring Cave?
What time is golden hour at Tyson Spring Cave?
Where does the sun rise and set at Tyson Spring Cave?
Can you see the Milky Way from Tyson Spring Cave?
Do you need a permit to photograph at Tyson Spring Cave?
How far is Tyson Spring Cave from Chatfield?
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.