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Best time to see the Milky Way in Petrified Forest National Park
April, May and June are the best months to see the Milky Way core at Petrified Forest National Park. The best week of 2027 is June 1 to 7, when the core is above 10 degrees in full darkness with the moon below the horizon for about 5.4 hours a night.
Apr, May and Jun
Best months for the core
26°
Highest point of the core, due south
43%
Average cloud amount over the year
73
Top core score out of 100, in June
The core clears 10 degrees during full darkness on most nights from February to October. In January, November and December it is 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 | 50% |
| February | 8 | February 10 to 16 | 0.6 | 50% |
| March | 26 | March 10 to 16 | 1.8 | 44% |
| April | 44 | April 6 to 12 | 3.0 | 40% |
| May | 65 | May 3 to 9 | 4.1 | 35% |
| June | 73 | June 1 to 7 | 5.4 | 27% |
| July | 42 | July 1 to 7 | 5.1 | 58% |
| August | 39 | August 1 to 7 | 3.3 | 53% |
| September | 26 | September 21 to 27 | 1.6 | 37% |
| October | 8 | October 1 to 7 | 0.5 | 32% |
| November | 0 | Core not visible | 0 | 39% |
| December | 0 | Core not visible | 0 | 53% |
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
- April: April 12 is the best night. The core is above 10 degrees and the moon is down from 1:19 am to 4:19 am, with the moon 42% lit that night.
- May: May 7 is the best night. The core is above 10 degrees and the moon is down from 11:39 pm to 3:39 am, with the moon 5% lit that night.
- June: June 4 is the best night. The core is above 10 degrees and the moon is down from 9:49 pm to 3:19 am, with the moon 0% lit that night.
Clock times are Mountain time, which does not observe daylight saving. The best nights fall around the new moon, so the dates shift by about 11 days each year.
About the park
Petrified Forest National Park is a national park in Arizona. The National Park Service places its center at 34.98 degrees north and 109.79 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.
How Petrified Forest National Park compares
Its best monthly core score of 73 ranks 11 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 Petrified Forest National Park runs from 27% in June to 58% in July.
The score ranks months and parks. It is not a forecast for any night, and it leaves out local weather, smoke and light from nearby towns. How the core score works.
Nearest parks
Sources and method
- Sun, Moon and galactic centre positions calculated for the park's latitude and longitude from the low-precision formulas in Paul Schlyter's "Computing planetary positions", with the standard sidereal-time and horizon formulas. The code is checked against known events: new and full moons within 5 minutes, and the September equinox within 1 minute.
- Cloud: monthly mean cloud amount, 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025), from NASA POWER (version v2.10.1, source SYN1DEG), accessed October 19, 2026. Data obtained from NASA Langley Research Center POWER Project.
- Park facts: National Park Service.