The core clears 10 degrees during full darkness on most nights from March to September. In January, February, October, November and December it's out of reach, either too close to the Sun or too low in the dark.
Core score by month
| Month | Core score | Best week | Moon-free core hours a night | Average cloud |
|---|---|---|---|---|
| January | 0 | Core not visible | 0 | 70% |
| February | 0 | No moon-free core hours | 0 | 68% |
| March | 7 | March 10 to 16 | 0.9 | 70% |
| April | 15 | April 6 to 12 | 1.8 | 65% |
| May | 30 | May 4 to 10 | 2.6 | 55% |
| June | 58 | June 1 to 7 | 3.7 | 38% |
| July | 72 | July 1 to 7 | 3.5 | 19% |
| August | 42 | August 1 to 7 | 2.1 | 21% |
| September | 14 | September 1 to 7 | 0.8 | 30% |
| October | 2 | October 1 to 7 | 0.1 | 46% |
| November | 0 | Core not visible | 0 | 67% |
| December | 0 | Core not visible | 0 | 73% |
Times are for the best seven nights in each month. Moon-free means the moon is below the horizon. The core counts as visible above 10 degrees in full darkness, when the Sun is more than 18 degrees below the horizon.
The best nights in 2027
- June: June 2 is the best night. The core is above 10 degrees and the moon is down from 11:38 pm to 3:18 am, with the moon 3% lit that night.
- July: July 1 is the best night. The core is above 10 degrees and the moon is down from 11:08 pm to 2:38 am, with the moon 5% lit that night.
- August: August 1 is the best night. The core is above 10 degrees and the moon is down from 10:28 pm to 12:38 am, with the moon 0% lit that night.
Clock times are Pacific time with daylight saving applied. The best nights fall around the new moon, so the dates shift by about 11 days each year.
About Crater Lake National Park
Crater Lake in southern Oregon is the deepest lake in the United States at almost 1,950 feet, and it's very blue. It fills the caldera of a volcano that blew itself apart around 7,700 years ago. Wizard Island, a small cinder cone, pokes up out of the water like a hat.
The Klamath people have a long connection to the lake and its story of the volcano. William Steel, an Oregon newspaperman, campaigned for protection for years, and the lake became a national park in 1902, one of the oldest in the country.
Crater Lake National Park is a national park in Oregon. The National Park Service places its center at 42.94 degrees north and 122.13 degrees west, and the sky calculations on this page use that point. Visitor information, fees and alerts are on the park's own page. National Park Service (opens in a new tab).
How Crater Lake National Park compares
Its best monthly core score of 72 ranks 12 of 54 national park units that can see the core. The highest is Lassen Volcanic National Park at 86, and the lowest is Voyageurs National Park at 13. Cloud at Crater Lake National Park runs from 19% in July to 73% in December.
The score ranks months and parks. It isn't a forecast for any night, and it leaves out local weather, smoke and light from nearby towns. How the core score works.
How dark is the sky?
The Park Service models how much artificial light brightens the sky across the lower 48. At the point used for Crater Lake National Park, it puts the added glow at about 5% of the natural brightness of a moonless sky (a ratio of 0.047). That makes it 8th darkest of the 47 parks it covers. Lower is darker. This is a model, not a reading taken at the park, and it describes one point, so the edges of a large park can differ.
Questions people ask
When is the best time to see the Milky Way at Crater Lake National Park?
June, July and August are the best months. The best week of 2027 is July 1 to 7.
Can you see the Milky Way at Crater Lake National Park all year?
The core clears 10 degrees during full darkness on most nights from March to September. In January, February, October, November and December it's out of reach, either too close to the Sun or too low in the dark.
How dark is the sky at Crater Lake National Park?
The Park Service models how much artificial light brightens the sky across the lower 48. At the point used for Crater Lake National Park, it puts the added glow at about 5% of the natural brightness of a moonless sky (a ratio of 0.047). That makes it 8th darkest of the 47 parks it covers. Lower is darker. This is a model, not a reading taken at the park, and it describes one point, so the edges of a large park can differ.
Does the moon matter at Crater Lake National Park?
Yes. A bright moon hides the Milky Way. The best night in July is July 1, when the moon is 5% lit and the core is above 10 degrees from 11:08 pm to 2:38 am.
