Located in Cook County, Minnesota, Hollow Rock is a natural arch at about 195 m (640 ft) above sea level. It sits roughly 48 km (30 mi) ENE of Grand Marais.
Sunrise & sunset directions
At Hollow Rock the sunrise point swings a long way through the year: about 53° (NE) at the June solstice and 125° (SE) in late December. Sunset moves from 308° (NW) in June to 235° (SW) in December, and the midday sun climbs to 66° in summer but only 19° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 7:03 AM | 89° E | 7:12 PM | 271° W | 42° | 12h 09m |
| June solstice (Jun 21) | 5:01 AM | 53° NE | 9:03 PM | 308° NW | 66° | 16h 02m |
| September equinox (Sep 22) | 6:46 AM | 89° E | 6:59 PM | 271° W | 42° | 12h 12m |
| December solstice (Dec 21) | 7:47 AM | 125° SE | 4:09 PM | 235° SW | 19° | 8h 23m |
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
Arches glow when reflected light bounces off nearby rock — the underside of an arch often turns bright orange just after sunrise or before sunset.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 7:09 AM | 7:44 AM | 8:35 AM | 3:43 PM | 4:34 PM | 5:09 PM | 8h 49m |
| February | 6:34 AM | 7:06 AM | 7:50 AM | 4:38 PM | 5:22 PM | 5:54 PM | 10h 15m |
| March | 6:42 AM | 7:13 AM | 7:54 AM | 6:23 PM | 7:04 PM | 7:35 PM | 11h 51m |
| April | 5:38 AM | 6:10 AM | 6:52 AM | 7:07 PM | 7:49 PM | 8:21 PM | 13h 39m |
| May | 4:44 AM | 5:21 AM | 6:07 AM | 7:46 PM | 8:31 PM | 9:08 PM | 15h 10m |
| June | 4:19 AM | 5:00 AM | 5:49 AM | 8:12 PM | 9:01 PM | 9:42 PM | 16h 00m |
| July | 4:37 AM | 5:16 AM | 6:03 AM | 8:08 PM | 8:55 PM | 9:34 PM | 15h 39m |
| August | 5:21 AM | 5:55 AM | 6:38 AM | 7:31 PM | 8:14 PM | 8:48 PM | 14h 19m |
| September | 6:06 AM | 6:37 AM | 7:18 AM | 6:33 PM | 7:13 PM | 7:45 PM | 12h 37m |
| October | 6:47 AM | 7:19 AM | 8:01 AM | 5:30 PM | 6:12 PM | 6:43 PM | 10h 54m |
| November | 6:32 AM | 7:06 AM | 7:54 AM | 3:35 PM | 4:23 PM | 4:57 PM | 9h 17m |
| December | 7:06 AM | 7:43 AM | 8:36 AM | 3:14 PM | 4:07 PM | 4:44 PM | 8h 25m |
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 Hollow Rock, the Milky Way core is visible in a dark sky from April through July. June gives the longest window (about 1.3 hours on a moonless night), and the core peaks around 13° 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 | — | -6° | — |
| February | Below 10° in darkness | — | 5° | — |
| March | Below 10° in darkness | — | 9° | — |
| April | 3:35 AM – 4:05 AM | 0.5 | 12° | SSE → SSE |
| May | 1:37 AM – 2:47 AM | 1.2 | 13° | SSE → S |
| June | 12:16 AM – 1:36 AM | 1.3 | 13° | SSE → S |
| July | 11:42 PM – 12:42 AM | 1.0 | 13° | S → SSW |
| August | 10:20 PM – 10:40 PM | 0.3 | 11° | SSW → SSW |
| September | Below 10° in darkness | — | 9° | — |
| October | Below 10° in darkness | — | 4° | — |
| November | Below 10° in darkness | — | -4° | — |
| 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 ≈ 21.95 mag/arcsec². Aurora needs roughly Kp 3.0+ to show low on the northern horizon here.
Weather & best season
Long-term NASA satellite data for this area show March as the clearest month (about 73% average cloud cover) and May as the cloudiest (89%). August is the warmest month and February 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 | 42 | 41 | 54 | 53 | 62 | 64 | 75 | 74 | 72 | 64 | 56 | 47 |
| Low °F | -12 | -10 | -6 | 14 | 26 | 36 | 39 | 50 | 40 | 30 | 13 | 4 |
| Precip. (in) | 1.7 | 1.4 | 1.6 | 2.8 | 3.2 | 3.5 | 3.1 | 2.8 | 3.1 | 3.1 | 2.0 | 2.2 |
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 natural arch
- Never climb on arches; many are fragile and climbing is prohibited on park lands.
- Midday sun creates hard shadows, but can light the underside through reflection in narrow canyons.
- Frame distant features through the opening of the arch for a natural window.
- At night, arches make classic Milky Way foregrounds; low-level lighting or blue hour exposures keep the rock detailed.
- Bring a spare battery — cold weather and long exposures drain them fast.
Season: Spring and autumn offer mild temperatures in desert arch country; summer heat is extreme at midday.
Suggested gear: Ultra-wide lens, Tripod, Headlamp, Plenty of water. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Nearby photo spots
Other locations within 25 km of Hollow Rock, closest first.
Mountain Peak
Waterfall
Scenic ViewpointWaterfall
State Park
State ParkWaterfall
Fire LookoutWaterfallCampgrounds nearby (Recreation.gov)
FAQ
When is the best time to photograph Hollow Rock?
What time is golden hour at Hollow Rock?
Where does the sun rise and set at Hollow Rock?
Can you see the Milky Way from Hollow Rock?
Do you need a permit to photograph at Hollow Rock?
How far is Hollow Rock from Grand Marais?
Sources
Location data: USGS GNIS / GeoNames. 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.