Space Weather
Kp Index — live and explained
The Kp index is the single most-watched number in space weather — a quick, global read on how disturbed Earth's magnetic field is right now.
Current Kp Index
Updated every 10 minutes from live NOAA data.
Source: NOAA SWPC
Storm Level
Why it matters
Kp is the single most useful number for predicting aurora visibility — it directly maps to how far from the poles the aurora oval expands. It's also the basis for NOAA's official G-scale geomagnetic storm classification, which utilities, satellite operators, and airlines use to anticipate real-world impacts like power grid stress, satellite drag, and radio disruption.
Normal range
Kp 0-2 is quiet, typical for most days. Kp 3-4 is unsettled but still common. Kp 5+ (G1 storm or higher) is where aurora becomes visible outside the polar regions, and happens on a meaningful minority of nights, more often near solar maximum. Kp 8-9 (G4-G5, extreme) is rare — a handful of times per solar cycle.
What today's value means
Waiting for live data to interpret…
What is the Kp index?
The planetary K-index (Kp) is a 0-to-9 scale measuring geomagnetic disturbance, calculated from magnetometer readings at observatories spread across the globe. It's published by NOAA's Space Weather Prediction Center and updated every three hours from ground stations, with an experimental 1-minute estimate available for near-real-time tracking — which is what powers the live number above. A quiet day sits around Kp 0-2; a major geomagnetic storm can push Kp to 8 or 9.
Kp level and aurora visibility
| Kp | G-Scale | Level | Typical aurora visibility |
|---|---|---|---|
| 0–2 | G0 | Quiet | No aurora activity beyond the polar regions. |
| 3–4 | G0 | Unsettled | Minor activity; aurora confined to high latitudes (Alaska, northern Canada, Scandinavia). |
| 5 | G1 | Minor storm | Aurora may become visible from the northern-tier US states and similar latitudes. |
| 6 | G2 | Moderate storm | Aurora visibility pushes further south, into the upper Midwest and Northeast. |
| 7 | G3 | Strong storm | Aurora can reach mid-latitude states. |
| 8–9 | G4–G5 | Severe–Extreme storm | Rare events; aurora can be visible as far south as the southern US. |
Actual visibility also depends on cloud cover, moonlight, and local light pollution — check the aurora forecast for your specific location.
Recent history
The last 24 hours of observed Kp values from this site's live feed.
FAQ
What Kp level do I need to see the aurora?
Kp 5 or higher (G1) typically brings aurora into view from the far northern US. Kp 7+ (G3) can push it into mid-latitude states, and Kp 8-9 (G4-G5) are rare events capable of bringing aurora as far south as the southern US.
How often does the Kp index update?
NOAA's official Kp is published every 3 hours; this page refreshes from a near-real-time estimate roughly every 10 minutes.
What's the highest Kp ever recorded?
Kp is capped at 9, the maximum on the scale — reached only during the most extreme geomagnetic storms, such as the May 2024 and October 2003 storms.