Arapaho Glacier is a glacier in Boulder County, Colorado at about 3,786 m (12,421 ft) above sea level. The nearest town is Nederland, about 13.6 km (8.5 mi) away (Arapaho Glacier lies WNW of town).
Arapaho Glacier is an alpine glacier in a cirque immediately southeast of North Arapaho Peak, in Roosevelt National Forest in the U.S. state of Colorado. The glacier is just east of the Continental Divide. Arapaho Glacier is the largest glacier in the state of Colorado and helps provide water for the city of Boulder, Colorado. The glacier has a negative glacier mass balance and lost over 52% of its surface area during the 20th Century.From the Wikipedia article “Arapaho Glacier”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Arapaho Glacier the sunrise point swings a long way through the year: about 58° (ENE) at the June solstice and 121° (ESE) in late December. Sunset moves from 302° (WNW) in June to 240° (WSW) in December, and the midday sun climbs to 73° in summer but only 27° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 7:07 AM | 90° E | 7:15 PM | 271° W | 50° | 12h 08m |
| June solstice (Jun 21) | 5:35 AM | 58° ENE | 8:36 PM | 302° WNW | 73° | 15h 01m |
| September equinox (Sep 22) | 6:51 AM | 89° E | 7:01 PM | 271° W | 50° | 12h 10m |
| December solstice (Dec 21) | 7:22 AM | 121° ESE | 4:41 PM | 240° WSW | 27° | 9h 19m |
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
Ice shows its blue best under overcast skies or in shade; bright sun turns glaciers white and flat.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 6:54 AM | 7:23 AM | 8:05 AM | 4:20 PM | 5:02 PM | 5:32 PM | 9h 39m |
| February | 6:29 AM | 6:57 AM | 7:34 AM | 5:01 PM | 5:39 PM | 6:07 PM | 10h 42m |
| March | 6:48 AM | 7:15 AM | 7:51 AM | 6:34 PM | 7:10 PM | 7:37 PM | 11h 55m |
| April | 5:57 AM | 6:25 AM | 7:02 AM | 7:05 PM | 7:41 PM | 8:09 PM | 13h 16m |
| May | 5:18 AM | 5:48 AM | 6:27 AM | 7:33 PM | 8:11 PM | 8:42 PM | 14h 23m |
| June | 5:01 AM | 5:34 AM | 6:15 AM | 7:53 PM | 8:34 PM | 9:07 PM | 15h 00m |
| July | 5:15 AM | 5:47 AM | 6:27 AM | 7:52 PM | 8:31 PM | 9:03 PM | 14h 44m |
| August | 5:46 AM | 6:15 AM | 6:52 AM | 7:24 PM | 8:01 PM | 8:30 PM | 13h 46m |
| September | 6:17 AM | 6:44 AM | 7:20 AM | 6:37 PM | 7:13 PM | 7:40 PM | 12h 29m |
| October | 6:46 AM | 7:14 AM | 7:50 AM | 5:48 PM | 6:24 PM | 6:52 PM | 11h 11m |
| November | 6:20 AM | 6:49 AM | 7:29 AM | 4:07 PM | 4:48 PM | 5:17 PM | 9h 59m |
| December | 6:48 AM | 7:18 AM | 8:01 AM | 3:56 PM | 4:39 PM | 5:10 PM | 9h 21m |
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 Arapaho Glacier, the Milky Way core is visible in a dark sky from March through September. June gives the longest window (about 4.8 hours on a moonless night), and the core peaks around 21° above the southern horizon. Our light-pollution model puts the sky at about Bortle 4 (rural / suburban transition), good enough for detailed Milky Way images.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | -3° | — |
| February | 5:10 AM – 5:20 AM | 0.2 | 11° | SE → SE |
| March | 4:20 AM – 5:40 AM | 1.3 | 18° | SE → SSE |
| April | 2:18 AM – 4:38 AM | 2.3 | 21° | SE → S |
| May | 12:22 AM – 3:52 AM | 3.5 | 21° | SE → S |
| June | 10:37 PM – 3:27 AM | 4.8 | 21° | SE → SSW |
| July | 10:29 PM – 1:59 AM | 3.5 | 21° | S → SW |
| August | 9:43 PM – 12:03 AM | 2.3 | 21° | S → SW |
| September | 8:45 PM – 9:55 PM | 1.2 | 18° | SSW → SW |
| October | 7:55 PM – 8:05 PM | 0.2 | 11° | SW → SW |
| November | Below 10° in darkness | — | 0° | — |
| 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: 4 Bortle 4 — Rural / suburban transition. Light domes are visible in several directions; the Milky Way is clear but lacks detail near the horizon. Modeled zenith brightness ≈ 21.1 mag/arcsec². Aurora needs roughly Kp 7.5+ 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 46% average cloud cover) and May as the cloudiest (67%). 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 | 46 | 48 | 65 | 71 | 83 | 89 | 90 | 88 | 85 | 74 | 62 | 50 |
| Low °F | -26 | -31 | -15 | -3 | 5 | 27 | 36 | 31 | 19 | -4 | -12 | -19 |
| Precip. (in) | 1.3 | 1.7 | 1.8 | 2.5 | 2.6 | 1.8 | 2.0 | 1.7 | 1.7 | 1.7 | 1.4 | 1.4 |
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 glacier
- A polarizer deepens the blue of glacial ice and the turquoise of meltwater lakes.
- Include a person or boat for scale — glaciers are much larger than they look.
- Boat tours to tidewater glaciers offer calving shots; use fast shutter speeds and a telephoto.
- Never walk on a glacier without training and gear; crevasses hide under snow bridges.
- Expose carefully: ice and snow fool meters into underexposure, so add +1 to +2 stops.
- Check road and trail conditions with the managing agency before you go.
Season: Summer offers access; late summer exposes the most bare ice before new snow.
Suggested gear: Telephoto lens, Polarizer, Waterproof shell, Spare batteries (cold drains them). Work out exposures with the depth of field, ND filter and NPF rule calculators.
Nearby photo spots
Other locations within 25 km of Arapaho Glacier, closest first.
Mountain Peak
Mountain Pass
Mountain Pass
Canyon
Mountain PeakMountain Pass
Ghost Town
Wilderness Area
Mountain PeakCampgrounds nearby (Recreation.gov)
- Rainbow Lakes Campground6.9 km (4.3 mi)
- Pawnee13.9 km (8.6 mi) · reservable
- Arapaho Bay14.1 km (8.8 mi) · reservable
- Camp Dick16.2 km (10.1 mi) · reservable
- Kelly Dahl16.3 km (10.1 mi) · reservable
FAQ
When is the best time to photograph Arapaho Glacier?
What time is golden hour at Arapaho Glacier?
Where does the sun rise and set at Arapaho Glacier?
Can you see the Milky Way from Arapaho Glacier?
Do you need a permit to photograph at Arapaho Glacier?
How far is Arapaho Glacier from Nederland?
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.