Located in Boulder County, Colorado, Flatirons is a mountain peak at about 2,181 m (7,156 ft) above sea level. The nearest town is Boulder, about 3.5 km (2.2 mi) away (Flatirons lies SSW of town).
The Flatirons are rock formations in the western United States, near Boulder, Colorado, consisting of flatirons. There are five large, numbered Flatirons ranging from north to south (First through Fifth, respectively) along the east slope of Green Mountain (elev. 8,148 ft or 2,484 m), and the term "The Flatirons" sometimes refers to these five alone. Numerous additional named Flatirons are on the southern part of Green Mountain, Bear Peak, and among the surrounding foothills. The rocks themselves are between 290-296 million years old. They are a popular rock-climbing location, with Mountain Project listing 1,427 climbing routes in The Flatirons. Many gather at Chautauqua Park in Boulder at the base of The Flatirons to enjoy the natural environment, preserved by Boulder Parks and Recreation. The Flatirons are an iconic symbol of Boulder, serving as the city's signature backdrop,...From the Wikipedia article “The Flatirons”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Flatirons 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) | 7:05 AM | 90° E | 7:13 PM | 271° W | 50° | 12h 08m |
| June solstice (Jun 21) | 5:33 AM | 58° ENE | 8:34 PM | 302° WNW | 73° | 15h 01m |
| September equinox (Sep 22) | 6:49 AM | 89° E | 7:00 PM | 271° W | 50° | 12h 10m |
| December solstice (Dec 21) | 7:20 AM | 121° ESE | 4:40 PM | 240° WSW | 27° | 9h 20m |
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
Summits catch first and last light — alpenglow can turn rock pink or orange minutes before sunrise and after sunset while valleys stay in shadow.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 6:52 AM | 7:22 AM | 8:03 AM | 4:19 PM | 5:01 PM | 5:30 PM | 9h 39m |
| February | 6:27 AM | 6:55 AM | 7:33 AM | 5:00 PM | 5:37 PM | 6:05 PM | 10h 42m |
| March | 6:47 AM | 7:14 AM | 7:49 AM | 6:32 PM | 7:08 PM | 7:35 PM | 11h 55m |
| April | 5:56 AM | 6:24 AM | 7:00 AM | 7:03 PM | 7:40 PM | 8:08 PM | 13h 16m |
| May | 5:16 AM | 5:47 AM | 6:26 AM | 7:31 PM | 8:10 PM | 8:41 PM | 14h 23m |
| June | 5:00 AM | 5:33 AM | 6:13 AM | 7:52 PM | 8:32 PM | 9:05 PM | 15h 00m |
| July | 5:14 AM | 5:46 AM | 6:25 AM | 7:50 PM | 8:30 PM | 9:02 PM | 14h 44m |
| August | 5:45 AM | 6:14 AM | 6:51 AM | 7:22 PM | 7:59 PM | 8:28 PM | 13h 46m |
| September | 6:16 AM | 6:43 AM | 7:19 AM | 6:36 PM | 7:12 PM | 7:39 PM | 12h 29m |
| October | 6:45 AM | 7:12 AM | 7:49 AM | 5:46 PM | 6:23 PM | 6:50 PM | 11h 11m |
| November | 6:18 AM | 6:47 AM | 7:27 AM | 4:06 PM | 4:46 PM | 5:15 PM | 9h 59m |
| December | 6:46 AM | 7:17 AM | 8:00 AM | 3:55 PM | 4:38 PM | 5:08 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 Flatirons, 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 7 (suburban / urban transition), 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 | — | -3° | — |
| February | 5:08 AM – 5:18 AM | 0.2 | 11° | SE → SE |
| March | 4:18 AM – 5:38 AM | 1.3 | 18° | SE → SSE |
| April | 2:16 AM – 4:36 AM | 2.3 | 21° | SE → S |
| May | 12:20 AM – 3:50 AM | 3.5 | 21° | SE → S |
| June | 10:35 PM – 3:25 AM | 4.8 | 21° | SE → SSW |
| July | 10:27 PM – 1:57 AM | 3.5 | 21° | S → SW |
| August | 9:41 PM – 12:01 AM | 2.3 | 21° | S → SW |
| September | 8:43 PM – 9:53 PM | 1.2 | 18° | SSW → SW |
| October | 7:53 PM – 8:03 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: 7 Bortle 7 — Suburban / urban transition. The whole sky has a grey-white glow; the Milky Way is invisible to the eye. Modeled zenith brightness ≈ 18.48 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 44% average cloud cover) and April as the cloudiest (64%). 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 | 46 | 47 | 64 | 68 | 81 | 86 | 87 | 85 | 82 | 73 | 62 | 49 |
| Low °F | -21 | -30 | -20 | -8 | 4 | 23 | 34 | 31 | 16 | -6 | -14 | -21 |
| Precip. (in) | 1.2 | 1.6 | 1.8 | 2.4 | 2.3 | 1.4 | 2.4 | 2.0 | 1.6 | 1.4 | 1.2 | 1.3 |
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 mountain peak
- Long lenses compress ridgelines; shoot the peak from several miles away to make it look massive.
- Afternoon thunderstorms are common in summer at high elevations — plan summit hikes for early morning.
- Snow on the summit holds detail best when you expose for the highlights and lift shadows later.
- Alpenglow lasts only a few minutes; set up and focus beforehand.
- Clouds around the summit add drama — a clear blue sky is often the least interesting condition.
- Tell someone where you're going in remote areas and carry the ten essentials.
Season: Early summer keeps snow on the peaks with green valleys below; autumn adds aspen or larch color in many ranges.
Suggested gear: Telephoto lens, Lightweight tripod, Warm layers, Microspikes in shoulder seasons. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Nearby photo spots
Other locations within 25 km of Flatirons, closest first.
Natural Arch
Mountain Peak
Botanical Garden
Mountain Peak
State Park
Mountain Peak
Waterfall
National Wildlife Refuge
CanyonCampgrounds nearby (Recreation.gov)
- Kelly Dahl18.5 km (11.5 mi) · reservable
- Rainbow Lakes Campground24 km (15 mi)
- Cold Springs - Arapaho Roosevelt Nf (Co)24 km (15 mi) · reservable
- Peaceful Valley24 km (15 mi) · reservable
- Camp Dick25 km (15 mi) · reservable
FAQ
When is the best time to photograph Flatirons?
What time is golden hour at Flatirons?
Where does the sun rise and set at Flatirons?
Can you see the Milky Way from Flatirons?
Do you need a permit to photograph at Flatirons?
How far is Flatirons from Boulder?
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.