Canada · International Dark Sky Park
Stargazing at Waterton-Glacier International Peace Park
How dark this certified sky really is, how far it is from the nearest cities, a live seven-night forecast for the site itself, and the moon-free nights worth planning around. Official DarkSky International page ↗
How dark the sky really is at Waterton-Glacier International Peace Park
Modelled zenith brightness at the site's coordinates is 21.74 mag/arcsec², which maps to roughly Bortle 3 (what each level means). This is an approximation from the 2024 light-pollution atlas, not a field measurement — and it describes the single point DarkSky lists, not the darkest corner of the park.
A genuinely dark rural sky: the Milky Way shows real structure overhead, galaxies and nebulae are rewarding in binoculars and small telescopes, and only a faint glow near the horizon betrays the nearest towns. For most visitors this is the darkest sky they will ever observe under.
Getting to Waterton-Glacier International Peace Park
The nearest cities we publish guides for, with the direction to head and a rough drive estimate.
- From Calgary
head south · 221.9 km straight-line · ≈288.5 km by road · ≈3.5 h · weekend trip
- From Edmonton
head south · 500.4 km straight-line · ≈650.5 km by road · ≈7.3 h · weekend trip
- From Seattle
head east · 642.9 km straight-line · ≈835.8 km by road · ≈9.3 h · weekend trip
Estimated from straight-line distance x a 1.3 road-detour factor and staged average speeds (40 km/h leaving town, 70 km/h regional, 95 km/h highway). It is a rough guide, not a routed drive time.
The next seven nights at Waterton-Glacier International Peace Park
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Plan the next 90 days at Waterton-Glacier International Peace Park
Moon-free dark windows are astronomy — computable years ahead. Cloud is not: beyond the 16-night forecast nobody knows the weather, and we won't pretend to. What five years of reanalysis can say is how often each month's nights actually stayed clear here.
- Nov 2–1514 moon-free nights19% of November nights here stayed clear (2021–2025)
- Dec 2–1413 moon-free nights10% of December nights here stayed clear (2021–2025)
- Dec 31 – Jan 1314 moon-free nights10% of December nights here stayed clear (2021–2025)
Clear nights by month, 2021–2025
- Jan21%
- Feb17%
- Mar31%
- Apr43%
- May52%
- Jun63%
- Jul80%
- Aug65%
- Sep72%
- Oct51%
- Nov19%
- Dec10%
Clearest months historically: July (80%), September (72%), August (65%); across the year 44% of nights with astronomical darkness stayed clear.
"Clear" = weighted cloud cover (low 0.5 / mid 0.3 / high 0.2) ≤ 20% across the night's astronomical darkness. ERA5 reanalysis via Open-Meteo Archive, 2021–2025 (CC BY 4.0) — historical frequency, not a forecast. Once a window comes within 16 nights, the live forecast above takes over.
Put Waterton-Glacier International Peace Park's dark-sky nights on your calendar
Every month has a stretch of nights when the Moon leaves the dark hours at Waterton-Glacier International Peace Park essentially moon-free. Subscribe once and each window lands in your own calendar, about a year ahead — no account, no email.
moon & darkness geometry only — cloud can't be known this far out; check the live forecast above when a window gets close
Questions people ask about Waterton-Glacier International Peace Park
- How dark is the sky at Waterton-Glacier International Peace Park?
- Modelled zenith brightness from the 2024 World Atlas of Artificial Night Sky Brightness puts Waterton-Glacier International Peace Park at about 21.74 mag/arcsec², roughly Bortle class 3. That is an approximation derived from satellite data, not a field measurement; it is certified by DarkSky International as an International Dark Sky Park.
- How far is Waterton-Glacier International Peace Park from Calgary?
- About 221.9 km in a straight line, heading south from Calgary. Using a 1.3 road-detour factor and staged average speeds that is roughly 288.5 km and 3.5 h of driving — an estimate, not a routed drive time.
- When is the next moon-free dark window at Waterton-Glacier International Peace Park?
- The next stretch of essentially moon-free dark hours runs Nov 2–15 (14 nights), computed from Moon phase and altitude with Skyfield and JPL DE440s. Cloud cannot be known that far ahead; the live seven-night forecast on this page shows real cloud cover once a window is close.
- What is the clearest month at Waterton-Glacier International Peace Park?
- Over 2021–2025, July (80%), September (72%), August (65%) had the highest share of nights with astronomical darkness that stayed clear (weighted cloud cover ≤ 20%); across the year it was 44%. ERA5 reanalysis via Open-Meteo — historical frequency, not a forecast.
Place name and coordinates: DarkSky International (reviewed 2026-07-15, data 2026-10-13). Light pollution: David Lorenz, World Atlas 2024 (EOG VIIRS, CC BY 4.0), approximate. Cloud: Open-Meteo.com (CC BY 4.0). Moon and darkness geometry: Skyfield + JPL DE440s, computed locally. Drive times are estimates, not routes.