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ERA5 climatology · 2015–2024
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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 · Finnsnes100 − mean cloud cover · higher is better

Clearest dark months here (outlined): Jan, Mar, Oct. Faint: no night with an hour of astronomical darkness — midnight sun (Jun, Jul); white nights, twilight only (Apr, May, Aug). Part-faint months are dark on some nights only: dark until 26 Mar; dark from 16 Sep. 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 Finnsnes — live →

Clearest dark skies in September

The aurora belt · Kp 3 or lessAll 70 spots

Top three: Fort McMurray, Yellowknife, Ilulissat. 45 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 · N41%6.7hKp 3+
  2. 02Yellowknife North America · N34%5.3hKp 1+
  3. 03Ilulissat Greenland · N· dark from 16 Sep33%4hKp 0+
  4. 04Whitehorse North America · N31%5.9hKp 3+
  5. 05Nuuk Greenland · N· dark from 3 Sep30%4.9hKp 1+
  6. 06Oulu Northern Europe · N· dark from 5 Sep29%4.7hKp 3+
  7. 07Kangerlussuaq Greenland · N· dark from 10 Sep29%4.4hKp 0+
  8. 08Dawson City North America · N· dark from 2 Sep28%4.8hKp 1+
  9. 09Fairbanks North America · N· dark from 4 Sep28%4.7hKp 1+
  10. 10Lofoten Islands Northern Europe · N· dark from 13 Sep27%4.1hKp 1+
  11. 11Svolvær Northern Europe · N· dark from 13 Sep26%4.1hKp 2+
  12. 12Tungeneset Northern Europe · N· dark from 17 Sep26%4hKp 1+
  13. 13Mefjordvær Northern Europe · N· dark from 17 Sep26%4hKp 1+
  14. 14Anchorage North America · N25%5.7hKp 3+
  15. 15Coldfoot / Bettles North America · N· dark from 11 Sep25%4.4hKp 0+
  16. 16Churchill North America · N24%6.3hKp 1+
  17. 17Rovaniemi Northern Europe · N· dark from 9 Sep24%4.5hKp 2+
  18. 18Gryllefjord Northern Europe · N· dark from 16 Sep24%3.9hKp 1+
  19. 19Reykjavík Northern Europe · N· dark from 3 Sep23%4.9hKp 2+
  20. 20Kiruna Northern Europe · N· dark from 12 Sep23%4.2hKp 2+
  21. 21Finnsnes Northern Europe · N· dark from 16 Sep23%4hKp 1+
  22. 22Senja Northern Europe · N· dark from 16 Sep23%3.9hKp 1+
  23. 23Mývatn Northern Europe · N· dark from 6 Sep22%4.6hKp 1+
  24. 24Nellim Northern Europe · N· dark from 15 Sep22%4.1hKp 2+
  25. 25Ivalo Northern Europe · N· dark from 14 Sep22%4hKp 2+
  26. 26Kirkenes Northern Europe · N· dark from 17 Sep22%3.8hKp 1+
  27. 27Faroe Islands (Tórshavn) Northern Europe · N21%5.5hKp 3+
  28. 28Vík Northern Europe · N21%4.9hKp 2+
  29. 29Inari Northern Europe · N· dark from 15 Sep21%4hKp 1+
  30. 30Tromsø Northern Europe · N· dark from 17 Sep21%3.9hKp 1+
  31. 31Iqaluit North America · N20%4.8hKp 1+
  32. 32Snæfellsnes (Kirkjufell) Northern Europe · N· dark from 5 Sep20%4.8hKp 2+
  33. 33Murmansk / Kola Peninsula Northern Europe · N· dark from 15 Sep20%4hKp 2+
  34. 34Lyngen Northern Europe · N· dark from 17 Sep20%3.9hKp 1+
  35. 35Alta Northern Europe · N· dark from 18 Sep20%3.8hKp 1+
  36. 36Denali North America · N19%5.1hKp 2+
  37. 37Þingvellir Northern Europe · N· dark from 3 Sep19%4.8hKp 2+
  38. 38Jökulsárlón Northern Europe · N· dark from 2 Sep19%4.8hKp 2+
  39. 39Akureyri Northern Europe · N· dark from 7 Sep19%4.7hKp 1+
  40. 40Saariselkä Northern Europe · N· dark from 14 Sep19%4.2hKp 2+
  41. 41Abisko Northern Europe · N· dark from 14 Sep17%4.2hKp 1+
  42. 42Skibotn Northern Europe · N· dark from 16 Sep17%3.9hKp 1+
  43. 43Iceland (countrywide) Northern Europe · N· dark from 4 Sep15%4.8hKp 2+
  44. 44Kilpisjärvi Northern Europe · N· dark from 16 Sep13%4.1hKp 1+
  45. 45Utqiaġvik (Barrow) North America · N· dark from 21 Sep11%3.4hKp 0+
clear = 100 − mean cloud cover · dark = mean hours of astronomical dark · glow = the spot's Kp for a glow

No true darkness in September

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.

White nights — twilight only

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 →