Space Weather Learning Hub

Kp Index, Explained

The planetary K-index (0–9) measures global geomagnetic disturbance over 3-hour blocks, derived from ground magnetometers. Higher Kp pushes the auroral oval toward lower latitudes.

Kp	NOAA	Aurora visibility (Earth)
0–2	Quiet	Far north/south only
3–4	Unsettled	High latitudes
5	G1Minor	Seen at mid-latitudes
6–7	G2–G3	Visible at lower latitudes
8–9	G4–G5	Extreme — rare events

Key caveat: Kp is a 3-hour average and is planetary, not local. A storm can highlight far south on the index while your skies stay quiet — and Kp 6 with northward Bz shows almost nothing visually.

Solar Flares & X-ray Classes

Solar X-ray emission is classified A → B → C → M → X, each step ×10. M and X flares can cause radio blackouts on the sunlit side of Earth. The flare_class on our dashboard maps directly to GOES flux.

Class	Effect	Frequency
A · B	Barely noticeable	Common
C	Minor radio effects	Common
M	HF radio blackouts	Weekly-ish
X	Major events, radiation	Rare

Note: a flare class is not a geomagnetic storm forecast. Only Earth-directed coronal mass ejections drive big storms — X-ray class alone doesn't predict them.

Solar Wind & IMF Bz

Solar wind carries the interplanetary magnetic field (IMF). Bz is the north–south component: sustained southward (negative) Bz is the primary driver of geomagnetic storms and aurora. Our dashboard shows northward or southward directly.

Space-Weather Glossary

• Kp — planetary geomagnetic index (0–9)
• Dst — ring-current magnetic disturbance
• F10.7 — solar radio flux at 10.7 cm (activity proxy)
• IMF — interplanetary magnetic field
• CME — coronal mass ejection
• SEP — solar energetic particles
• G scale — geomagnetic storm scale (G1–G5)
• R scale — radio blackout scale (R1–R5)
• S scale — solar radiation storm scale (S1–S5)