The best month.
Pick a month and every watch point is ranked by its real monthly cloud cover — 2015–2024 reanalysis means, lower is better — with the spots that have no true darkness that month set apart. Or pick a spot for its twelve-month chart.
Clearest dark months here (outlined): Feb, Jun, Aug. ERA5 reanalysis, 2015–2024 monthly mean. Climatology, not a forecast — a regional ~25 km grid; local microclimates are not captured. Darkness & moon calendar → Best month, all spots →
Clearest dark skies in June
Top three: South Africa (Cape Point / Hermanus), North Dakota, Montana (Glacier NP). 23 watch points with at least one night of an hour's astronomical darkness this month, ranked by clear sky (100 − mean cloud cover); dark hours are the mean over the month's dark nights, and a part-dark month says when its darkness starts or ends. Cloud is only one of the three conditions — a clear Kp 9 spot is almost never lit; the threshold shown is each spot's own.
- South Africa (Cape Point / Hermanus)
- North Dakota
- Montana (Glacier NP)
- South Australia coast (Kangaroo Is.)
- Northern Minnesota (Voyageurs)
- Dunedin / Otago Peninsula
- Michigan Upper Peninsula (Keweenaw)
- Launceston
- Christchurch
- Hobart
- Lake Tekapo (Aoraki Mackenzie)
- Northern Maine (Acadia)
- Victoria coast (Phillip Island)
- Washington (North Cascades)
- Patagonia (El Calafate)
- Bruny Island / Cockle Creek
- Punta Arenas
- Invercargill
- Falkland Islands
- Stewart Island / Rakiura
- Ushuaia / Tierra del Fuego
- Queenstown / Southland
- South Georgia
No true darkness in June
No night this month reaches an hour of astronomical darkness — clear or not, the aurora is not visible. Their cloud figures are shown for the record.
- Abisko · 75%
- Alta · 77%
- Coldfoot / Bettles · 62%
- Ilulissat · 68%
- Inari · 74%
- Ivalo · 72%
- Kangerlussuaq · 73%
- Kilpisjärvi · 75%
- Kirkenes · 77%
- Kiruna · 68%
- Lofoten Islands · 70%
- Lyngen · 78%
- Murmansk / Kola Peninsula · 76%
- Nellim · 71%
- Rovaniemi · 66%
- Saariselkä · 72%
- Senja · 76%
- Skibotn · 79%
- Svalbard (Longyearbyen) · 85%
- Svolvær · 71%
- Tromsø · 78%
- Utqiaġvik (Barrow) · 83%
- Aberdeenshire · 71%
- Akureyri · 80%
- Anchorage · 68%
- Caithness (north Highlands) · 77%
- Churchill · 70%
- Copenhagen · 57%
- Dawson City · 66%
- Denali · 81%
- Donegal · 78%
- Edinburgh · 71%
- Edmonton · 59%
- Estonia (Tartu / coast) · 55%
- Fairbanks · 62%
- Faroe Islands (Tórshavn) · 82%
- Fort McMurray · 62%
- Helsinki · 51%
- Iceland (countrywide) · 83%
- Iqaluit · 80%
- Jasper · 68%
- Nuuk · 79%
- Orkney · 74%
- Oslo · 59%
- Oulu · 58%
- Reykjavík · 81%
- Shetland · 77%
- Stockholm · 54%
- Whitehorse · 67%
- Yellowknife · 59%
Cloud: Open-Meteo Historical Weather API (ERA5 reanalysis), cloud_cover_mean (daily), averaged by calendar month, 2015–2024. Climatology, not a forecast — a regional ~25 km grid; local microclimates (a valley's "blue hole") are not captured. Darkness: astronomical (sun below −18°) computed for the 15th of the month at each spot. Night-by-night darkness & moon → Season sheet (PDF) → Plan the trip →