Schumann Pulse
The interactive space-weather chart lab
Kp describes planetary disturbance. Dst tracks a change in the low-latitude field. Bz describes one component of the upstream magnetic field. Adjust three independent examples and see why one number cannot tell the whole story.
Authored examples, not live readings or forecasts · reviewed 22 October 2026
Kp index · three-hour intervals
Hour in an invented UTC day
Gold line: G1 begins at Kp 5.
Eight invented three-hour intervals in an example UTC day. Only the outlined 12–15 bar changes. Kp uses a quasi-logarithmic index scale, not nT.
Change only the 12–15 interval. Each bar covers three hours. These teaching controls use integers; official Kp also has intermediate third-step values.
The selected interval starts at minute 30. Its length is not an Earth-arrival estimate or a storm threshold.
What this tells you
The 12–15 example interval is Kp 5: Minor geomagnetic storm level (G1). This is a three-hour index, not an instantaneous reading or a prediction of local aurora.
Understand the Kp index ↗| Example UTC hours | Kp |
|---|---|
| 00–03 | 2 |
| 03–06 | 2 |
| 06–09 | 3 |
| 09–12 | 4 |
| 12–15 | 5 |
| 15–18 | 4 |
| 18–21 | 3 |
| 21–24 | 2 |
This example shows the Kp lesson. Read all three explanations below; no live data is used.
01 / Kp
Kp combines standardized ground-observatory indices into a planetary measure for each three-hour UTC interval. It runs from 0 to 9 on a quasi-logarithmic scale. Kp 6 does not mean twice the physical disturbance of Kp 3.
The lab uses integer steps to make the NOAA storm levels easy to explore: Kp 5, 6, 7, 8 and 9 correspond to Minor, Moderate, Strong, Severe and Extreme (G1–G5). Official Kp also includes intermediate third-step values.
Read the Kp guide ↗02 / Dst
Dst is an hourly index in nanotesla (nT), derived from four low-latitude observatories after background and regular daily variations are removed. It reflects several large-scale current systems, including the ring, tail and magnetopause currents.
A negative value describes a depression of the horizontal field relative to its reference. Positive values can occur too. The example’s early positive bump and later dip are teaching choices; real storms have varied shapes and timing.
Read the Dst explanation ↗03 / Bz
Bz is the z-component of the solar-wind magnetic field. In the GSM coordinates used here, a negative value is southward and a positive value is northward. A zero z-component does not mean that the total field is zero.
A sustained southward field can favour energy transfer into Earth’s magnetosphere. Duration, solar-wind speed and other conditions matter. A single negative sample cannot determine a storm level or guarantee a local aurora.
Read the solar-wind guide ↗Before putting the charts together
These lessons are separate examples, not successive stages of one event. The Kp and Dst plots show invented days; Bz shows a shorter upstream interval. Their values are not calculated from one another.
Compare Kp, Dst and Bz in detail ↗Bz describes an upstream component; Kp summarises a three-hour ground response. Check persistence, the surrounding solar-wind conditions and the time periods being compared. The difference alone does not diagnose an event, and this lab does not simulate a delayed response.
There is no universal direct conversion. Dst and Bz share the unit nT but refer to different quantities and locations; Kp uses its own index scale. Adding them or putting them on a shared unlabelled vertical axis would hide those differences.
No. Location, darkness, clouds, the auroral oval and the timing of activity all matter. An index can provide context without confirming what you will see. Our aurora viewing guide explains the practical checks.
The examples use fixed axes and invented values so you can see exactly what each control changes. They are not observations, a storm simulation or an assessment of personal health effects.
Kp: eight three-hour bars from 00 to 24 in an invented UTC day. Only 12–15 changes. The G labels apply to the integer values in this lesson; the chart is not a complete lookup for all official third-step values. A zero value has a visible marker rather than a missing bar.
Dst: 24 invented hourly averages, plotted at each hour’s centre. The adjustable minimum scales a fixed dip and recovery shape; a separate +30 nT bump is unchanged. Connecting lines guide the eye and do not add observations between hours. The fixed vertical scale is +50 to −200 nT.
Bz: three constant segments over 120 example minutes. The selected segment starts at minute 30; its value and duration change independently. The rest stays at +5 nT. The fixed scale is −20 to +20 nT. The duration is not a physical threshold or a prediction of travel time to Earth.
Each lesson includes a readable table of the plotted values. Switch lessons to reset that example; use “Reset this lesson” to restore its starting values.
Original explanatory content by Schumann Pulse. See how we source and review the field guide.
From an example to an observation
Our current space-weather page shows NOAA Kp with its source and interval. Keep completed intervals separate from a running estimate. The lab does not add a live Dst or Bz feed.
See space weather todayYour daily perspective
In Schumann Pulse, choose activity alerts and record feelings, optional energy and sleep quality. Revisit your journal and suitable personal comparisons as your history grows. An environmental index cannot tell you why you feel a certain way.
Explore what you can track ↗Coming soon for iPhone. History and personal comparisons live in the app.