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): Jan, Mar, Sep. Faint: no night with an hour of astronomical darkness — white nights, twilight only (May, Jun, Jul, Aug). Part-faint months are dark on some nights only: dark until 7 Apr; dark from 4 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 →
Clearest dark skies in July
0 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.
No true darkness in July
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.
- Akureyri · 83%
- Anchorage · 72%
- Churchill · 65%
- Coldfoot / Bettles · 68%
- Dawson City · 66%
- Denali · 86%
- Fairbanks · 68%
- Faroe Islands (Tórshavn) · 84%
- Fort McMurray · 57%
- Iceland (countrywide) · 81%
- Iqaluit · 78%
- Kangerlussuaq · 65%
- Nuuk · 75%
- Oulu · 63%
- Reykjavík · 79%
- Rovaniemi · 68%
- Whitehorse · 68%
- Yellowknife · 56%
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 →