Twin Sisters Mountain is a mountain peak in Whatcom County, Washington at about 1,710 m (5,610 ft) above sea level. It sits roughly 26 km (16 mi) E of Sudden Valley.
Twin Sisters Mountain (Nooksack: Kwetl’kwítl’ Smánit, "red mountain"), commonly called the Twin Sisters, is a mountain in the U.S. state of Washington. Part of the Cascade Range, it lies just southwest of Mount Baker. Of its two main peaks, South Twin is higher, with a summit elevation above 7,004 feet (2,135 m). The summit of North Twin is above 6,644 feet (2,025 m). There are several glaciers on the northeast slopes of Twin Sisters Mountain.From the Wikipedia article “Twin Sisters Mountain”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Twin Sisters Mountain the sunrise point swings a long way through the year: about 52° (NE) at the June solstice and 126° (SE) in late December. Sunset moves from 308° (NW) in June to 234° (SW) in December, and the midday sun climbs to 65° in summer but only 18° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 7:12 AM | 89° E | 7:21 PM | 271° W | 41° | 12h 09m |
| June solstice (Jun 21) | 5:06 AM | 52° NE | 9:15 PM | 308° NW | 65° | 16h 09m |
| September equinox (Sep 22) | 6:55 AM | 89° E | 7:08 PM | 271° W | 42° | 12h 12m |
| December solstice (Dec 21) | 7:59 AM | 126° SE | 4:15 PM | 234° SW | 18° | 8h 16m |
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 | 7:20 AM | 7:56 AM | 8:48 AM | 3:48 PM | 4:40 PM | 5:16 PM | 8h 44m |
| February | 6:44 AM | 7:17 AM | 8:02 AM | 4:44 PM | 5:29 PM | 6:02 PM | 10h 13m |
| March | 6:51 AM | 7:22 AM | 8:04 AM | 6:32 PM | 7:13 PM | 7:45 PM | 11h 51m |
| April | 5:45 AM | 6:18 AM | 7:00 AM | 7:17 PM | 7:59 PM | 8:32 PM | 13h 42m |
| May | 4:50 AM | 5:28 AM | 6:14 AM | 7:57 PM | 8:43 PM | 9:21 PM | 15h 15m |
| June | 4:23 AM | 5:05 AM | 5:55 AM | 8:24 PM | 9:13 PM | 9:55 PM | 16h 08m |
| July | 4:42 AM | 5:22 AM | 6:10 AM | 8:19 PM | 9:07 PM | 9:47 PM | 15h 45m |
| August | 5:27 AM | 6:02 AM | 6:46 AM | 7:41 PM | 8:25 PM | 9:00 PM | 14h 23m |
| September | 6:14 AM | 6:46 AM | 7:27 AM | 6:41 PM | 7:23 PM | 7:54 PM | 12h 37m |
| October | 6:57 AM | 7:29 AM | 8:12 AM | 5:37 PM | 6:20 PM | 6:52 PM | 10h 51m |
| November | 6:43 AM | 7:17 AM | 8:07 AM | 3:40 PM | 4:30 PM | 5:04 PM | 9h 12m |
| December | 7:18 AM | 7:55 AM | 8:50 AM | 3:18 PM | 4:13 PM | 4:50 PM | 8h 18m |
Local time (America/Los Angeles), 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 Twin Sisters Mountain, the Milky Way core is visible in a dark sky from May through July. June gives the longest window (about 2.7 hours on a moonless night), and the core peaks around 12° 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 | — | -5° | — |
| February | Below 10° in darkness | — | 4° | — |
| March | Below 10° in darkness | — | 9° | — |
| April | 3:58 AM – 4:08 AM | 0.2 | 11° | SSE → SSE |
| May | 1:55 AM – 2:45 AM | 0.8 | 12° | SSE → S |
| June | 11:56 PM – 2:36 AM | 2.7 | 12° | SSE → SSW |
| July | 12:04 AM – 12:44 AM | 0.7 | 12° | S → SSW |
| August | 10:34 PM – 10:34 PM | 0.0 | 10° | SSW → SSW |
| September | Below 10° in darkness | — | 8° | — |
| October | Below 10° in darkness | — | 4° | — |
| November | Below 10° in darkness | — | -5° | — |
| 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 ≈ 21.51 mag/arcsec². Aurora needs roughly Kp 4.0+ to show low on the northern horizon here.
Weather & best season
Long-term NASA satellite data for this area show July as the clearest month (about 42% average cloud cover) and November as the cloudiest (76%). August 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 | 47 | 50 | 56 | 68 | 77 | 87 | 90 | 90 | 86 | 76 | 55 | 41 |
| Low °F | -20 | -17 | -12 | 1 | 16 | 28 | 34 | 35 | 24 | -2 | -17 | -20 |
| Precip. (in) | 9.5 | 6.5 | 7.5 | 4.8 | 3.6 | 3.0 | 1.3 | 1.7 | 3.4 | 7.2 | 10.7 | 9.1 |
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
- Clouds around the summit add drama — a clear blue sky is often the least interesting condition.
- Photograph the peak from a lake, meadow or ridge at sunrise when the face that looks east lights up first.
- 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.
- Bring a spare battery — cold weather and long exposures drain them fast.
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 Twin Sisters Mountain, closest first.
Fire Lookout
Glacier
Glacier
VolcanoVolcano
Glacier
Mountain Peak
Glacier
WaterfallCampgrounds nearby (Recreation.gov)
- Boulder Creek Campground21 km (13 mi) · reservable
- Douglas Fir Campground23 km (14 mi) · reservable
- Bayview Campground (Mt. Baker-Snoqualmie National Forest, Wa)23 km (14 mi) · reservable
- Horseshoe Cove Campground23 km (14 mi) · reservable
- Panorama Point Campground23 km (14 mi) · reservable
FAQ
When is the best time to photograph Twin Sisters Mountain?
What time is golden hour at Twin Sisters Mountain?
Where does the sun rise and set at Twin Sisters Mountain?
Can you see the Milky Way from Twin Sisters Mountain?
Do you need a permit to photograph at Twin Sisters Mountain?
How far is Twin Sisters Mountain from Sudden Valley?
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.