Aurora Forecast Tonight and Northern Lights Tracker

Auroras form when solar wind particles, funneled by Earth's magnetic field, collide with oxygen and nitrogen atoms high in the atmosphere. Those collisions release the familiar green, red, and violet light.

The Kp index measures geomagnetic disturbance on a 0–9 scale. Higher Kp pushes the auroral oval southward (or northward in the southern hemisphere), making the aurora visible from more populated latitudes.

• Kp 0–2 — quiet, aurora only at high polar latitudes.
• Kp 3–4 — unsettled / active, visible from Alaska, northern Canada, Scandinavia.
• Kp 5 — minor storm (G1), possibly visible from the northern US, UK, southern Scandinavia.
• Kp 6–7 — moderate to strong storm (G2–G3), visible from the central US and central Europe.
• Kp 8–9 — severe to extreme storm (G4–G5), aurora reported as far south as Texas or Spain.

Solar wind speed and the Bz component of the interplanetary magnetic field shape how strong any given storm becomes; a sustained southward Bz is what really opens the magnetic door.

Beyond the spectacle, geomagnetic storms can disturb power grids, satellite navigation, and high-frequency radio. The same forecast that tells aurora chasers when to drive north is used by grid operators and pilots to plan around space weather.