How dark is the sky at Gateway Arch National Park?
When is Milky Way season near Gateway Arch National Park 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 38.6° north the core peaks at about 22° 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.
Has the sky over Gateway Arch National Park 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.
Clear nights at Gateway Arch National Park by month
The average number of nights each month with less than 30% cloud, from NASA POWER satellite records.
Lights around Gateway Arch National Park seen from orbit
NASA satellite image of light at night, 2025. The rings mark distances from Gateway Arch National Park.
Where can you drive to the darkest sky at Gateway Arch National Park?
The darkest viewpoints, campgrounds, parking areas and trailheads you can drive to, up to about 60 km from the center of Gateway Arch National Park. Drive times from St. Louis, the nearest town of 5,000 people or more (1 km W).
None of these spots can be reached by car: there are no roads to them, or only by ferry or a long hike. Use them to see where the darkest land is.
A spot closed at night, or a number that looks wrong? Let us know.
Where are the observatories near Gateway Arch National Park?
Observatories within 150 km, with the modeled sky at each. Older ones often sit inside towns, newer ones were built where it is dark. Many are research or club sites, so check opening times before you go.
Almost black on purpose: there's next to no artificial light within this circle. This is what a dark sky looks like from orbit.
Which towns light up the Gateway Arch National Park 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 Gateway Arch National Park's own outskirts.
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