Will the northern lights be worth going outside for tonight? Nordlys answers that, and tells you why when the answer is no.
NEVER JUST "0%"
Most aurora apps show one number. When it reads zero you learn nothing — is the sun quiet, is it cloudy, or is it simply the middle of the afternoon? Nordlys separates them. Four things have to be true at once, and you can see at a glance which one is missing.
DARK · CLEAR · MOON · ACTIVE
Darkness where you stand, cloud cover for your sky, how bright the moon is, and what the sun is actually doing. All four, all the time, in plain language.
THE FAST NUMBERS, NOT JUST Kp
Kp is a three-hour global average. It is useful for planning a week, and far too slow to tell you about the next hour. Nordlys also watches Bz — the direction of the solar wind's magnetic field — which turns south minutes before an aurora arrives and is what the slower models are still catching up to.
TONIGHT, HOUR BY HOUR
Darkness, cloud and activity layered on one chart, with the best window picked out. No cross-referencing three screens.
ALERTS YOU CAN BELIEVE
One alert when it is genuinely worth putting a coat on. Never in daylight. Never under heavy cloud. Never twice for the same event. And a log of every single check, so if no alert came you can see exactly what stopped it — no other aurora app will tell you that.
HONEST ABOUT WHAT IT KNOWS
Every reading shows when it was measured and goes visibly stale. Nothing is presented as live when it is an hour old. Substorms are not predictable at thirty minutes, so Nordlys says "low" rather than pretending "none".
FREE, AND STAYING FREE
Every reading, the three-day forecast, the aurora map, tonight's hourly chart, and one working alert. The data comes from NOAA, who give it away, and we never charge for it.
Nordlys Pro adds more places, your own alert threshold, quiet hours, and control over how often alerts can arrive.
No ads. No tracking. Your saved places stay on your device.
Data from NOAA Space Weather Prediction Center and Open-Meteo.
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