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): Apr, Aug, Sep. Faint: no night with an hour of astronomical darkness — white nights, twilight only (Jun). Part-faint months are dark on some nights only: dark until 14 May; dark from 28 Jul. 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 December
Top three: South Africa (Cape Point / Hermanus), South Australia coast (Kangaroo Is.), Victoria coast (Phillip Island). 68 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)
- South Australia coast (Kangaroo Is.)
- Victoria coast (Phillip Island)
- Launceston
- North Dakota
- Coldfoot / Bettles
- Edmonton
- Hobart
- Northern Maine (Acadia)
- Christchurch
- Fairbanks
- Lake Tekapo (Aoraki Mackenzie)
- Fort McMurray
- Bruny Island / Cockle Creek
- Ilulissat
- Queenstown / Southland
- Nuuk
- Yellowknife
- Aberdeenshire
- Jasper
- Dunedin / Otago Peninsula
- Denali
- Invercargill
- Kangerlussuaq
- Reykjavík
- Edinburgh
- Whitehorse
- Orkney
- Lofoten Islands
- Iqaluit
- Faroe Islands (Tórshavn)
- Shetland
- Oslo
- Caithness (north Highlands)
- Svalbard (Longyearbyen)
- Svolvær
- Dawson City
- Stockholm
- Stewart Island / Rakiura
- Copenhagen
- Senja
- Kirkenes
- Kiruna
- Washington (North Cascades)
- Alta
- Anchorage
- Donegal
- Northern Minnesota (Voyageurs)
- Montana (Glacier NP)
- Utqiaġvik (Barrow)
- Inari
- Helsinki
- Churchill
- Ivalo
- Nellim
- Iceland (countrywide)
- Oulu
- Lyngen
- Murmansk / Kola Peninsula
- Rovaniemi
- Tromsø
- Saariselkä
- Akureyri
- Estonia (Tartu / coast)
- Michigan Upper Peninsula (Keweenaw)
- Skibotn
- Abisko
- Kilpisjärvi
No true darkness in December
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.
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 →