Space Weather Dashboard Basics

Kp, ap, F10.7, solar wind, and storm levels — what each number is for, and what it is not.

Key Takeaways

Kp is the main number to know. A 0–9 planetary index that describes geomagnetic disturbance, updated every three hours, built from a network of ground-based observatories.
ap is Kp’s maths-friendly cousin. A linearised version used when you want to average or compare values over time, because Kp’s scale is quasi-logarithmic and cannot be averaged directly.
F10.7 tells you about background solar activity, not whether a storm is happening right now. It is a daily radio-flux reading that tracks long-term solar conditions.
Solar wind speed and Bz are the real-time storm drivers, especially Bz. When it turns and stays southward for hours, that is what actually feeds a geomagnetic storm.
The NOAA G-scale (G1–G5) translates Kp into plain-language storm severity. G1 starts at Kp 5, G5 is Kp 9.
Kp is not a symptom index. It was built for tracking impacts on power grids, satellites, radio, and aurora. It does not measure anything about human physiology.

The Numbers Behind the Headlines

When a big solar storm hits the news, dashboards light up with numbers: Kp = 7, F10.7 = 180, Bz = -20 nT. Aurora-chasers know what these mean. For everyone else, the dashboard looks like a weather app in a language you almost speak but cannot quite read.

This is a field guide to those numbers: what each one actually measures, where the data comes from, and what it is for and what it is not.

Kp: The Number Everyone Talks About

A Kp strip is just eight three-hour bins. Green is quiet, amber is unsettled, and red is storm territory.

Kp is the planetary geomagnetic index. It runs from 0 to 9, updated in three-hour blocks (timed to Universal Time), and describes how disturbed Earth’s magnetic field was across a global network of ground stations. When people say “Kp is 6” or “Kp hit 8,” this is what they are referring to.

The number is derived from 13 subauroral observatories spread around the world. Each station measures the range of irregular magnetic variation at its location over a three-hour window, generating a local K-index (also 0–9). Those local values are then standardised and combined into the single planetary Kp figure. The standardisation means Kp accounts for the fact that magnetic sensitivity varies with latitude; a station closer to the poles sees more natural variation.

A few things worth knowing:

Kp is expressed in thirds. You will see values like 4-, 4, 4+, or equivalently 3.67, 4.00, 4.33. The “+” and “-” notation is the most common on dashboards.
“Estimated Kp” and “definitive Kp” are different. What you see in real time on a dashboard is a nowcast estimate. The finalised, quality-checked values come later, published by GFZ Potsdam, the IAGA-endorsed producer of the definitive Kp record.
The local K-index at a specific observatory can look quite different from Kp, especially at higher latitudes. If a dashboard shows a local K value from a single station, it is not the same thing as the planetary Kp.

ap and Ap: Why There’s a Second Set of Numbers

You will sometimes see ap alongside Kp, especially in data tables or more technical dashboards. They track the same thing, but the maths behind them matters.

Kp’s scale is quasi-logarithmic, which is useful for representing a wide range of disturbance levels but means you cannot just add Kp values together and take an average. That is where ap comes in. It is a linearised “equivalent range” value derived from Kp using a conversion table published by NOAA NCEI. The ap scale runs from 0 to 400.

Ap (capital A) is then the daily average of those eight three-hour ap values, giving a single number that summarises the magnetic activity level for a whole day.

In practice: if you are just watching a live dashboard to understand what is happening now, Kp is the number to follow. If you are doing any kind of analysis across days or weeks — building a personal dataset, comparing storm periods — ap and Ap are the right ones to work with.

F10.7: Background Solar Activity, Not a Storm Alarm

F10.7 tells you where the sun is in the broader cycle, not whether a storm is hitting Earth right now.

F10.7 is the 10.7 cm solar radio flux — a measure of solar radio emissions at 2800 MHz, recorded daily (typically at noon, local time) from Penticton, Canada, where the measurement programme has been running continuously since 1947. Values are reported in solar flux units (sfu) and typically range from around 70 sfu at solar minimum to above 300 sfu at solar maximum.

What it tracks: F10.7 correlates well with sunspot number and with solar UV and EUV emissions that affect the ionosphere. That makes it a useful indicator of background solar activity levels — where we are in the solar cycle, whether the sun is generally active or quiet.

What it does not tell you: whether a geomagnetic storm is happening right now. A high F10.7 means the sun is generally active; it does not mean a storm is imminent or ongoing. If you see a headline with an F10.7 value, that is context for the broader solar environment, not an alert.

Solar Wind: The Real-Time Picture

L1 solar-wind monitors are useful because they give a short warning window, but the window is measured in minutes, not days.

The data that tells you what is actually driving Earth’s magnetic field right now comes from spacecraft monitoring the solar wind at the L1 Lagrange point, a gravitational balance point about 1.5 million kilometres sunward of Earth. NOAA’s operational spacecraft there has been DSCOVR since 2016, with the older ACE spacecraft as a backup.

A key practical note: L1 measurements give only about 15 to 60 minutes of lead time before the solar wind reaches Earth. The window varies with solar wind speed. This is why space weather “forecasting” is hard; you are often working with very short notice.

The four parameters that matter most for understanding storm conditions:

Speed (km/s) — faster solar wind generally means more energy input; high-speed streams from coronal holes can drive moderate sustained storms.
Density (particles per cm³) — denser solar wind means more mass arriving; spikes often accompany CME leading edges.
Bt (total field, in nanotesla) — the overall strength of the solar wind magnetic field.
Bz (north-south component, GSM, in nanotesla) — the crucial one.

Bz is what matters most for storm development. When Bz turns southward (negative values) and stays there for an extended period, the solar wind magnetic field is oriented opposite to Earth’s dayside field. That geometry allows efficient energy transfer into the magnetosphere, which is what drives a geomagnetic storm. A brief southward dip does little. Sustained southward Bz over hours is what produces the significant storm events.

If you are watching a live solar-wind feed and want to know whether conditions are storm-genic: Bz sustained at -10 nT or more negative for several hours is where things get serious.

The G-Scale: How Storms Get Labelled

NOAA’s Space Weather Scales give storms a simple severity rating from G1 to G5, based directly on Kp.

G1 / Kp 5 — minor storm conditions; some grid fluctuation risk at high latitudes and aurora possible in high-latitude regions.
G2 / Kp 6 — moderate storm conditions; transformer issues become more plausible at high latitudes and aurora can reach farther south.
G3 / Kp 7 — strong storm conditions; operators may need corrections and aurora can become visible around 50° latitude.
G4 / Kp 8 — severe storm conditions; voltage-control problems become more widespread and aurora can reach much farther south.
G5 / Kp 9 — extreme storm conditions with the broadest infrastructure effects and the lowest-latitude aurora visibility.

The G-scale was designed to communicate infrastructure impacts: what power operators, satellite operators, and radio communications need to think about. It is the same index aurora-chasers use to plan a night out, but the scale was not built with personal health or wellness in mind. It describes geophysical disturbance severity, not anything else.

Where to Get the Data

Two tiers, depending on what you want to do with the data.

For live monitoring — NOAA SWPC is the place to start. Their site has live Kp displays, solar-wind plots, alerts, and F10.7 readings. For programmatic access, SWPC’s JSON endpoints are widely used in community dashboards and scripts, but note an important format change: SWPC issued Service Change Notice SCN 26-21 stating that several JSON products are being restructured (effective 31 March 2026), and that older RTSW solar-wind files are being deprecated (30 April 2026). The replacement endpoints are under /json/rtsw/: use rtsw_mag_1m.json and rtsw_wind_1m.json rather than the older mag-1-day.json format if you are building anything that needs to keep working.

For historical analysis — two sources stand out. GFZ Potsdam is the IAGA-endorsed distributor of definitive Kp, ap, and Ap data, with an API and clear provenance flags distinguishing nowcast from finalised values. NASA OMNIWeb provides a long-term (1963 to present) compiled, time-shifted near-Earth solar wind dataset, the standard resource for retrospective solar-wind analysis.

What These Numbers Are Not

A quick note on some things that circulate widely in health and wellness spaces alongside space weather content.

Kp is not a symptom index. It is a planetary geomagnetic disturbance index built from observatory magnetometers, designed for operational space weather monitoring. NOAA frames its primary users as power-grid operators, satellite operators, and aurora observers. The index was not constructed to measure anything about human physiology, and it does not.

Schumann resonances are not the same as space weather indices. Schumann resonances are standing electromagnetic waves in the cavity between Earth’s surface and the ionosphere, driven primarily by global lightning activity, not by solar storms directly. Dashboards showing Schumann-resonance data are measuring something real, but it is a different thing from Kp or solar wind.

F10.7 is not a real-time storm alert. A high daily F10.7 reading means the sun is in an active period. It does not mean a storm is happening or imminent.

These distinctions are not pedantic; they matter for how you interpret what you are reading. When you know what each index actually measures, it is easy to see when a dashboard or social post is mixing up different signals.

FAQ

What’s the simplest way to think about Kp?

It is a 0–9 score for how disturbed Earth’s magnetic field is, updated every three hours. Quiet days sit around 0–2. Anything above 5 starts getting interesting for aurora watchers and means a minor geomagnetic storm is in progress. Kp = 9 is an extreme event — rare, and the kind that makes the news.

What actually causes a geomagnetic storm?

The main driver is sustained southward Bz in the solar wind. When the solar wind’s magnetic field is oriented opposite to Earth’s dayside field for several hours, energy transfers efficiently into the magnetosphere, which drives storm conditions. A CME hitting Earth does not automatically mean a big storm; it depends heavily on what Bz does when it arrives.

Why does my dashboard show a different K value from the Kp I see elsewhere?

Local K-index readings from a single observatory can look quite different from the planetary Kp, especially at higher latitudes. If a dashboard or app is showing a local K-index rather than the derived planetary Kp, the numbers are not directly comparable. Check which one the source is using.

Is there a health connection to geomagnetic storms?

The research here is genuinely mixed. Some observational studies find correlations between geomagnetic indices and various physiological measures; others find the effects weaken or disappear after correcting for time-series confounders and multiple comparisons. The indices were not designed for this purpose, and no strong causal mechanism has been established. Treating Kp as a health alert goes beyond what the science currently supports.

What’s the best free source for Kp data?

For live monitoring: NOAA SWPC. For historical analysis and definitive (quality-checked) values: GFZ Potsdam. Both are free and well-maintained.

Glossary

Kp index — the planetary geomagnetic index, 0–9, built from a standardised network of 13 subauroral observatories. Updated every three hours. The primary real-time geomagnetic disturbance indicator used in space weather dashboards.

K-index — a local equivalent of Kp at a single observatory, also 0–9. Values differ by station and latitude; not directly comparable to planetary Kp.

ap — a linearised version of the Kp value (scale 0–400), derived from Kp via a conversion table. Used when you want to mathematically average or sum geomagnetic activity values, since Kp’s quasi-logarithmic scale does not support direct averaging.

Ap — the daily mean of the eight three-hour ap values, giving a single day-level geomagnetic activity summary.

F10.7 — the 10.7 cm solar radio flux, measured daily from Penticton, Canada since 1947. A proxy for background solar activity and ionospheric conditions; not a real-time storm indicator.

Solar wind — the continuous stream of charged particles emitted by the Sun. Key parameters for storm forecasting: speed (km/s), density (cm⁻³), Bt (total field strength in nT), and Bz (north-south magnetic component in nT).

Bz (GSM) — the north-south component of the solar-wind magnetic field in Geocentric Solar Magnetospheric coordinates. Southward (negative) Bz sustained over hours is the main driver of geomagnetic storm development.

NOAA G-scale — the NOAA Space Weather Scale for geomagnetic storms, G1 (minor, Kp = 5) through G5 (extreme, Kp = 9). Designed to communicate expected infrastructure impacts.

L1 point — the Lagrange gravitational balance point about 1.5 million km sunward of Earth, where NOAA’s DSCOVR spacecraft monitors real-time solar wind. Provides roughly 15–60 minutes of lead time before conditions reach Earth.

Schumann resonances — standing electromagnetic resonances in the Earth–ionosphere cavity, driven primarily by global lightning activity. Not a solar storm index; a distinct measurement from space weather indices.

Where the science stands

The geophysics is well-established and operational. Kp, ap, F10.7, and L1 solar-wind monitoring are mature, internationally coordinated systems run by NOAA SWPC, GFZ Potsdam (the IAGA-endorsed definitive Kp source), and NASA OMNIWeb. The infrastructure-impact framing (G-scale) reflects forty years of operational space-weather practice. The contested territory is downstream: the question of whether geomagnetic disturbance has measurable health effects in humans, where the literature is mixed and where no causal mechanism is established at the scale of consumer dashboards. The honest summary is: read the indices for what they are (geophysical monitoring), not as health alerts.

Related on SolarHealth

Solar & Geophysical pillar — the broader hub for heliobiology, space weather, and Earth-based geophysical signals.
Geomagnetic storms and HRV — personal tracking protocol — companion guide on how to use these indices in a structured personal-data experiment.
Solar and geomagnetic parameters — the deeper reference on Kp, ap, and related metrics.
Heliobiology mechanisms — for the question of how solar variability might (or might not) couple to biology.
Live Data dashboard — current solar and geomagnetic conditions while you read.

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Disclaimer

This article is for general information and educational purposes. It does not constitute medical advice. Space weather indices are geophysical monitoring tools; they were not designed to assess human health outcomes and should not be interpreted as health indicators.