Aurora tonight
Peaks at Kp 3.7 around 05:00
Light nights. The sun never drops far enough below the horizon. First dark night 29 August.
The nights ahead
Geomagnetic forecast. Seeing it still needs darknessSolar wind now
Last hour · DSCOVRA southward field opens Earth's magnetic field. Everything below the dashed line helps. Lowest −0.5 nT at 09:48.
The auroral oval
NOAA OVATION · 30-minute forecastNorthern hemisphere
Ovation
Solar wind in space
WSA-EnlilThe sun now
Coronagraphs and EUVLASCO C2
SOHOLASCO C3
SOHOCCOR-1
GOES-19SUVI 171 Å
GOES-19Sunspots
SDO HMIC2 shows the inner corona, C3 the outer. The white streaks are particles hitting the camera.
Alerts
NOAA SWPC · last 24 hoursNo active alerts.
Understanding the aurora
What is the aurora?
Charged particles from the sun follow Earth's magnetic field down towards the poles and collide with oxygen and nitrogen high in the atmosphere. Those collisions emit light: green from oxygen around 100 km, red higher up, violet from nitrogen.
Why do Bz and solar wind matter?
Bz is the direction of the magnetic field carried by the solar wind. When it points south, meaning negative, it links up with Earth's own field and lets energy in. A strongly southward Bz and a high speed produce aurora even at moderate Kp.
What does the Kp number mean?
Kp measures global geomagnetic disturbance on a scale from 0 to 9. At Sortland, Kp 2–3 is enough for aurora to the north, while Kp 5 and above drags the oval so far south that the light stands directly overhead.
When is the season?
From late August to the middle of April. For the rest of the year the sun sits too high at night. The activity can be just as good, but the sky is too bright for anything to show.