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National monument

How dark is the sky at Mount St. Helens National Volcanic Monument?

Coordinates
Satellite data year 2025 · Clear-night record 2014 to 2023
Zenith sky brightness, moonless night
mag/arcsec²
22.0 pristine16.0 city center
Bortle class
Artificial light adds to the natural brightness of the sky overhead.
Calculated in advance for 2027 · not a weather forecast

When will the Milky Way be visible at Mount St. Helens National Volcanic Monument in 2027?

Nights in each month when the Milky Way core stands more than 10° above the horizon for at least an hour of moonless astronomical darkness. At 46.2° north the core peaks at about 15° high, so a clear southern horizon matters. These are calculated positions of the sun, moon and Milky Way; whether a night is clear is only known closer to the date.

Expected best nights in 2027, combining moonless darkness, Milky Way core time and average clear-night odds
New moons 2027, calculated
2012 to 2025

Has the sky over Mount St. Helens National Volcanic Monument gotten brighter?

Each point is how much artificial light added to the natural brightness of the sky overhead that year: 0% is a natural sky, 100% means twice as bright. Same satellite every year; it barely sees the blue part of white LED light, so recent years probably read too dark.

Nightly cloud record 2014 to 2023

Clear nights at Mount St. Helens National Volcanic Monument by month

The average number of nights each month with less than 30% cloud, from NASA POWER satellite records.

Light map · 100 km around Mount St. Helens National Volcanic Monument

Lights around Mount St. Helens National Volcanic Monument seen from orbit

NASA satellite image of light at night, 2025. The rings mark distances from Mount St. Helens National Volcanic Monument.

Where can you drive to the darkest sky at Mount St. Helens National Volcanic Monument?

The darkest viewpoints, campgrounds, parking areas and trailheads you can drive to, up to about 60 km from the center of Mount St. Helens National Volcanic Monument. Drive times from Morton, the nearest town (37 km N).

    A spot closed at night, or a number that looks wrong? Let us know.

    Satellite night-light map of the 100 km around Mount St. Helens National Volcanic Monument, with Portland, Vancouver and Gresham marked
    Radiance, nW/cm²/sr
    0110300+
    Light domes · where the glow comes from

    Which towns light up the Mount St. Helens National Volcanic Monument horizon?

    The compass shows where the glow on the horizon comes from, counting all light more than 5 km away. The table names the towns behind it, including Mount St. Helens National Volcanic Monument's own outskirts.

    SourceDistanceShare

    The horizon at Mount St. Helens National Volcanic Monument, all 360°, brighter where more glow arrives
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