Skip to content
ERA5 climatology · 2015–2024
When to go

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.

Clear sky by month · Patagonia (El Calafate)100 − mean cloud cover · higher is better

Clearest dark months here (outlined): Jan, Sep, Nov. Faint: no night with an hour of astronomical darkness — white nights, twilight only (Dec). Part-faint months are dark on some nights only: dark from 13 Jan; dark until 27 Nov. 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 →

● Tonight at Patagonia (El Calafate) — live →

Clearest dark skies in October

The aurora belt · Kp 3 or lessAll 70 spots

Top three: Fort McMurray, Nuuk, Ilulissat. 37 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.

  1. 01Fort McMurray North America · N35%9.4hKp 3+
  2. 02Nuuk Greenland · N34%8.9hKp 1+
  3. 03Ilulissat Greenland · N33%8.3hKp 0+
  4. 04Fairbanks North America · N30%8.9hKp 1+
  5. 05Kangerlussuaq Greenland · N29%8.6hKp 0+
  6. 06Lofoten Islands Northern Europe · N29%8.4hKp 1+
  7. 07Dawson City North America · N28%8.9hKp 1+
  8. 08Coldfoot / Bettles North America · N28%8.6hKp 0+
  9. 09Svolvær Northern Europe · N28%8.4hKp 2+
  10. 10Anchorage North America · N26%9.2hKp 3+
  11. 11Whitehorse North America · N24%9.2hKp 3+
  12. 12Denali North America · N24%9hKp 2+
  13. 13Oulu Northern Europe · N24%8.8hKp 3+
  14. 14Reykjavík Northern Europe · N23%8.9hKp 2+
  15. 15Kiruna Northern Europe · N23%8.5hKp 2+
  16. 16Senja Northern Europe · N23%8.3hKp 1+
  17. 17Kirkenes Northern Europe · N23%8.2hKp 1+
  18. 18Yellowknife North America · N22%9.1hKp 1+
  19. 19Inari Northern Europe · N22%8.3hKp 1+
  20. 20Faroe Islands (Tórshavn) Northern Europe · N21%9.1hKp 3+
  21. 21Rovaniemi Northern Europe · N21%8.7hKp 2+
  22. 22Ivalo Northern Europe · N21%8.4hKp 2+
  23. 23Nellim Northern Europe · N20%8.3hKp 2+
  24. 24Tromsø Northern Europe · N20%8.2hKp 1+
  25. 25Churchill North America · N19%9.3hKp 1+
  26. 26Alta Northern Europe · N19%8.1hKp 1+
  27. 27Iqaluit North America · N18%9hKp 1+
  28. 28Saariselkä Northern Europe · N18%8.4hKp 2+
  29. 29Murmansk / Kola Peninsula Northern Europe · N18%8.3hKp 2+
  30. 30Lyngen Northern Europe · N18%8.2hKp 1+
  31. 31Akureyri Northern Europe · N15%8.8hKp 1+
  32. 32Svalbard (Longyearbyen) Northern Europe · N· dark from 9 Oct14%6.4hKp 0+
  33. 33Abisko Northern Europe · N13%8.4hKp 1+
  34. 34Skibotn Northern Europe · N13%8.3hKp 1+
  35. 35Utqiaġvik (Barrow) North America · N13%7.9hKp 0+
  36. 36Iceland (countrywide) Northern Europe · N12%8.9hKp 2+
  37. 37Kilpisjärvi Northern Europe · N10%8.3hKp 1+
clear = 100 − mean cloud cover · dark = mean hours of astronomical dark · glow = the spot's Kp for a glow

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 →