Alert · Space Weather · 14:53
Issue Time: 2026 Jul 27 1453 UTC
Aurora tonight
Aurora activity
1.7Kp
Little chance tonight
Peaks at Kp 3.7 around 23:00
Light nights — the sun never drops far enough below the horizon. First dark night 29 August.
Tonight · Kp by the hourCalmActiveStorm
Kp 3.7
18202200020406
Bt
8.6 nT
Density
2.6 p/cm³
Power
14 GW
Storm
G0
No storm
The nights ahead
Geomagnetic forecast — seeing it still needs darknessNight to Thursday 30 Jul
3.0Kp
Best window—
Little chanceNight to Friday 31 Jul
4.0Kp
Best windowBeyond the forecast
Little chanceSolar wind now
Last hour · DSCOVRBz · field direction−8 … +8 nT
+1.4nTnorthward — unfavourable
10:4911:0711:2611:44
A southward field opens Earth's magnetic field — everything below the dashed line helps. Lowest +1.2 nT at 11:36.
Speed350–380 km/s
363km/s
10:4911:0711:2611:44
The auroral oval
NOAA OVATION · 30-minute forecastNorthern hemisphere
OvationLoading
Solar wind in space
WSA-EnlilImage unavailable
The sun now
Coronagraphs and EUVLASCO C2
SOHOImage unavailable
LASCO C3
SOHOImage unavailable
CCOR-1
GOES-19Image unavailable
SUVI 171 Å
GOES-19Image unavailable
Sunspots
SDO HMIImage unavailable
C2 shows the inner corona, C3 the outer. The white streaks are particles hitting the camera.
Alerts
NOAA SWPC · last 24 hoursUnderstanding 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.