Located in Imperial County, California, Imperial National Wildlife Refuge is a national wildlife refuge. It sits roughly 40 km (25 mi) N of Yuma.
The Imperial National Wildlife Refuge protects wildlife habitat along 30 miles (50 km) of the lower Colorado River in Arizona and California, including the last un-channeled section before the river enters Mexico. The Imperial Refuge Wilderness, a federally designated, 15,056-acre (60.93 km2), wilderness area is protected within the refuge. It also surrounds the Picacho State Recreation Area. This section of the Colorado River is popular for boating, hiking, fishing, camping, exploring old mining camps and wildlife watching. The river and its associated backwater lakes and wetlands are a green oasis, contrasting with the surrounding desert mountains. It is a refuge and breeding area for migratory birds and local desert wildlife.From the Wikipedia article “Imperial National Wildlife Refuge”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Imperial National Wildlife Refuge the sunrise point swings a long way through the year: about 61° (ENE) at the June solstice and 118° (ESE) in late December. Sunset moves from 299° (WNW) in June to 242° (WSW) in December, and the midday sun climbs to 80° in summer but only 33° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 6:43 AM | 90° E | 6:51 PM | 271° W | 57° | 12h 07m |
| June solstice (Jun 21) | 5:31 AM | 61° ENE | 7:51 PM | 299° WNW | 80° | 14h 20m |
| September equinox (Sep 22) | 6:28 AM | 89° E | 6:37 PM | 271° W | 57° | 12h 09m |
| December solstice (Dec 21) | 6:39 AM | 118° ESE | 4:37 PM | 242° WSW | 33° | 9h 58m |
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
Wildlife is most active in the first and last two hours of daylight — exactly when the light is warmest.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 6:16 AM | 6:43 AM | 7:19 AM | 4:18 PM | 4:55 PM | 5:22 PM | 10h 12m |
| February | 5:58 AM | 6:23 AM | 6:57 AM | 4:50 PM | 5:24 PM | 5:50 PM | 11h 01m |
| March | 6:25 AM | 6:50 AM | 7:23 AM | 6:14 PM | 6:47 PM | 7:12 PM | 11h 57m |
| April | 5:44 AM | 6:09 AM | 6:43 AM | 6:36 PM | 7:09 PM | 7:35 PM | 13h 00m |
| May | 5:13 AM | 5:40 AM | 6:15 AM | 6:57 PM | 7:32 PM | 7:59 PM | 13h 52m |
| June | 5:02 AM | 5:30 AM | 6:07 AM | 7:13 PM | 7:50 PM | 8:19 PM | 14h 19m |
| July | 5:13 AM | 5:41 AM | 6:17 AM | 7:13 PM | 7:49 PM | 8:17 PM | 14h 08m |
| August | 5:36 AM | 6:03 AM | 6:36 AM | 6:52 PM | 7:26 PM | 7:52 PM | 13h 23m |
| September | 5:58 AM | 6:23 AM | 6:56 AM | 6:14 PM | 6:47 PM | 7:11 PM | 12h 23m |
| October | 6:19 AM | 6:44 AM | 7:17 AM | 5:33 PM | 6:07 PM | 6:32 PM | 11h 23m |
| November | 5:44 AM | 6:10 AM | 6:46 AM | 4:02 PM | 4:38 PM | 5:04 PM | 10h 28m |
| December | 6:08 AM | 6:35 AM | 7:13 AM | 3:56 PM | 4:34 PM | 5:02 PM | 9h 59m |
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 Imperial National Wildlife Refuge, the Milky Way core is visible in a dark sky from February through October. June gives the longest window (about 6.2 hours on a moonless night), and the core peaks around 28° above the southern horizon. Our light-pollution model puts the sky at about Bortle 2 (typical truly dark site), which is excellent for astrophotography.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | 1° | — |
| February | 4:08 AM – 4:58 AM | 0.8 | 17° | SE → SE |
| March | 3:20 AM – 5:20 AM | 2.0 | 24° | SE → SSE |
| April | 1:16 AM – 4:36 AM | 3.3 | 28° | SE → S |
| May | 11:17 PM – 3:57 AM | 4.7 | 28° | SE → SSW |
| June | 9:32 PM – 3:42 AM | 6.2 | 28° | SE → SW |
| July | 9:28 PM – 2:18 AM | 4.8 | 28° | SSE → SW |
| August | 8:56 PM – 12:16 AM | 3.3 | 28° | S → SW |
| September | 8:10 PM – 10:10 PM | 2.0 | 25° | SSW → SW |
| October | 7:29 PM – 8:19 PM | 0.8 | 17° | SW → SW |
| November | Below 10° in darkness | — | 3° | — |
| December | Below 10° in darkness | — | -18° | — |
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: 2 Bortle 2 — Typical truly dark site. The summer Milky Way shows rich structure; clouds look like black holes in the stars. Modeled zenith brightness ≈ 21.7 mag/arcsec².
Weather & best season
Long-term NASA satellite data for this area show June as the clearest month (about 14% average cloud cover) and December as the cloudiest (38%). 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 | 87 | 90 | 99 | 104 | 114 | 123 | 121 | 118 | 118 | 108 | 97 | 84 |
| Low °F | 24 | 24 | 33 | 40 | 47 | 56 | 66 | 64 | 55 | 38 | 30 | 28 |
| Precip. (in) | 0.6 | 0.6 | 0.4 | 0.1 | 0.1 | 0.0 | 0.5 | 0.6 | 0.5 | 0.4 | 0.5 | 0.5 |
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 national wildlife refuge
- Migration peaks bring the largest concentrations — see the birding calendar for this state.
- Use auto-loop roads as mobile blinds; animals often tolerate vehicles more than people on foot.
- Stay on designated routes and keep a respectful distance — if an animal changes behavior, you are too close.
- A 400–600 mm lens (or a crop body) is the usual tool for birds.
- Shoot RAW to keep the most latitude for high-contrast sunrise and sunset scenes.
Season: Spring and autumn migration are the highlights; winter brings waterfowl to many southern refuges.
Suggested gear: Telephoto lens (400 mm+), Bean bag for car window, Binoculars. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Permits, drones & access
Drones: Launching or landing drones on National Wildlife Refuge lands generally requires a special use permit from the refuge manager, and wildlife disturbance rules apply everywhere.
Nearby photo spots
Other locations within 40 km of Imperial National Wildlife Refuge, closest first.
Waterfall
Scenic ViewpointScenic Viewpoint
Wilderness AreaWaterfallScenic Viewpoint
State ParkScenic Viewpoint
Wilderness AreaCampgrounds nearby (Recreation.gov)
FAQ
When is the best time to photograph Imperial National Wildlife Refuge?
What time is golden hour at Imperial National Wildlife Refuge?
Where does the sun rise and set at Imperial National Wildlife Refuge?
Can you see the Milky Way from Imperial National Wildlife Refuge?
Do you need a permit to photograph at Imperial National Wildlife Refuge?
How far is Imperial National Wildlife Refuge from Yuma?
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.