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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 · South Africa (Cape Point / Hermanus)100 − mean cloud cover · higher is better

Clearest dark months here (outlined): Jan, Feb, Dec. 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 South Africa (Cape Point / Hermanus) — live →

Clearest dark skies in August

The aurora belt · Kp 3 or lessAll 70 spots

Top three: Montana (Glacier NP), North Dakota, Washington (North Cascades). 43 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. 01Montana (Glacier NP) North America · N59%5.4hKp 5+
  2. 02North Dakota North America · N58%5.6hKp 5+
  3. 03Washington (North Cascades) North America · N57%5.4hKp 6+
  4. 04South Africa (Cape Point / Hermanus) Africa · S54%10.3hKp 9+
  5. 05Michigan Upper Peninsula (Keweenaw) North America · N50%5.8hKp 5+
  6. 06Edmonton North America · N48%4hKp 4+
  7. 07Northern Minnesota (Voyageurs) North America · N46%5.6hKp 5+
  8. 08South Australia coast (Kangaroo Is.) Oceania · S45%10.3hKp 7+
  9. 09Fort McMurray North America · N· dark from 12 Aug44%3.5hKp 3+
  10. 10Copenhagen Northern Europe · N· dark from 8 Aug43%3.6hKp 5+
  11. 11Christchurch Oceania · S41%10.4hKp 6+
  12. 12Northern Maine (Acadia) North America · N41%6hKp 5+
  13. 13Jasper North America · N41%4.2hKp 4+
  14. 14Yellowknife North America · N· dark from 29 Aug41%1.8hKp 1+
  15. 15Stockholm Northern Europe · N· dark from 20 Aug40%2.9hKp 4+
  16. 16Helsinki Northern Europe · N· dark from 22 Aug40%2.6hKp 4+
  17. 17Victoria coast (Phillip Island) Oceania · S39%10.3hKp 6+
  18. 18Estonia (Tartu / coast) Northern Europe · N· dark from 17 Aug39%3hKp 5+
  19. 19Dunedin / Otago Peninsula Oceania · S38%10.4hKp 5+
  20. 20Lake Tekapo (Aoraki Mackenzie) Oceania · S38%10.4hKp 5+
  21. 21Launceston Oceania · S38%10.3hKp 5+
  22. 22Oslo Northern Europe · N· dark from 22 Aug38%2.8hKp 4+
  23. 23Hobart Oceania · S37%10.4hKp 5+
  24. 24Patagonia (El Calafate) South America · S33%10.4hKp 9+
  25. 25Churchill North America · N· dark from 18 Aug33%3hKp 1+
  26. 26Whitehorse North America · N· dark from 24 Aug32%2.5hKp 3+
  27. 27Bruny Island / Cockle Creek Oceania · S31%10.4hKp 4+
  28. 28Invercargill Oceania · S31%10.4hKp 5+
  29. 29Edinburgh Northern Europe · N· dark from 9 Aug31%3.6hKp 5+
  30. 30Aberdeenshire Northern Europe · N· dark from 13 Aug31%3.4hKp 5+
  31. 31Punta Arenas South America · S30%10.4hKp 9+
  32. 32Anchorage North America · N· dark from 25 Aug29%2.2hKp 3+
  33. 33Orkney Northern Europe · N· dark from 19 Aug28%3hKp 5+
  34. 34Falkland Islands South Atlantic · S27%10.4hKp 9+
  35. 35Caithness (north Highlands) Northern Europe · N· dark from 17 Aug25%3.1hKp 5+
  36. 36Shetland Northern Europe · N· dark from 23 Aug24%2.6hKp 4+
  37. 37Donegal Northern Europe · N· dark from 4 Aug22%3.7hKp 5+
  38. 38Faroe Islands (Tórshavn) Northern Europe · N· dark from 28 Aug22%2.1hKp 3+
  39. 39Stewart Island / Rakiura Oceania · S21%10.4hKp 4+
  40. 40Ushuaia / Tierra del Fuego South America · S21%10.3hKp 8+
  41. 41Queenstown / Southland Oceania · S18%10.4hKp 5+
  42. 42Denali North America · N· dark from 31 Aug13%1.6hKp 2+
  43. 43South Georgia South Atlantic · S9%10.3hKp 8+
clear = 100 − mean cloud cover · dark = mean hours of astronomical dark · glow = the spot's Kp for a glow

No true darkness in August

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.

Midnight sun — the sun never sets

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 →