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Milky Way season, park by park

54 national park units, ranked by how good their best month is for seeing the Milky Way core. Lassen Volcanic National Park comes first at 86 out of 100, and Voyageurs National Park comes last at 13. Each park page has its best dates for 2027, worked out for that park's own latitude, longitude and cloud record.

The top six

Every park, ranked

Eight of Alaska's national parks are not in the table, because from there the core never gets high enough to see. Why, and what you can see instead.

How the core score works

The score runs from 0 to 100. For each month it takes the best seven nights and averages the hours when the galactic core is more than 10 degrees above the horizon, the Sun is more than 18 degrees below it and the Moon is below the horizon. It caps that at four hours, then multiplies by the share of the month the park is not under cloud on average. A score of 0 means the core cannot be seen that month, or the Moon is up whenever it is.

The positions of the Sun, Moon and core are calculated from published formulas and checked against known moon phases and equinoxes. Cloud is a monthly NASA satellite average from 2001 to 2025 for a grid cell roughly 100 km across, covering day and night. The score does not include local weather, smoke, haze, light from nearby towns or a park's measured sky darkness. It ranks months and parks. It is not a forecast for any night.

The core is the brightest part of the Milky Way. The fainter band through Cygnus and Cassiopeia is high in the evening sky from late summer into autumn, when the core is out of reach.