Each location gets a score of
0–10 for how good the aurora conditions are:
- Cloud cover – split into low/mid/high clouds. Low clouds block the aurora; high, thin veil clouds you can see through.
- View to the north (counts most) – we measure the clouds both overhead and ~39 km to the north, since the aurora often sits in the north.
- Aurora activity (Kp) – higher Kp = stronger and more likely aurora.
- Moonlight – a dark sky gives better contrast.
What the numbers mean in practice:
- 8–10 – Clear sky, or only thin high clouds. If the aurora is out, you'll see it clearly. Perfect for bringing guests.
- 6–8 – Mostly clear with some clouds; the aurora shows well in the gaps. Worth heading out.
- 4–6 – Partly cloudy, some low clouds. Glimpses possible but uncertain – watch for it to clear.
- 2–4 – Lots of low clouds. Little chance, even if the aurora is out.
- 0–2 – Dense cloud cover, the aurora is blocked. Wait, or drive somewhere else.
The number tells you how good the
viewing conditions are. Whether the aurora actually appears depends on solar activity (Kp) – a high number means "you'll see it
if it's there".
"Cloud cover" = how much of the sky is blocked (0 % fully clear → 100 % fully covered), calculated as a mix of directly overhead (45 %) and to the north (55 %). Built on a live weather & aurora forecast. Locations with avalanche risk are flagged for safety.