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AsteriaStar
Live · NOAA SWPC & NASA DONKI

Current conditions

What the Sun and the near-Earth environment are doing right now, from the agencies that measure them. Every reading below shows when it was taken.

Solar wind at L1

  • Speed

    Live

    495km/s

    Moderate

    Typical solar wind speed. The magnetosphere is being pushed at an ordinary rate.

    Measured
    2026-09-17 08:02 UTC
    Type
    Observation
    Provider
    NOAA Space Weather Prediction Center

  • Proton density

    Live

    3.15cm^-3

    Measured
    2026-09-17 08:02 UTC
    Type
    Model product
    Provider
    NOAA Space Weather Prediction Center

    Observed at L1 and advected to Earth's bow shock nose by SWPC's propagation model.

  • Field strength (Bt)

    Live

    4nT

    Measured
    2026-09-17 08:02 UTC
    Type
    Observation
    Provider
    NOAA Space Weather Prediction Center

  • North–south field (Bz)

    Live

    2nT

    Near neutral

    The field has little north–south component. Coupling is modest and can change quickly — Bz varies on a timescale of minutes.

    Measured
    2026-09-17 08:02 UTC
    Type
    Observation
    Provider
    NOAA Space Weather Prediction Center

These are measured about 1.5 million kilometres sunward of Earth, at the L1 Lagrange point. At the speeds shown, that is roughly half an hour to an hour of travel time before the same plasma reaches us.

Geomagnetic activity

Planetary K-index (latest observed)

Recent

1.67

Quiet

Very quiet; aurora confined to high polar latitudes. Below Kp 5 there is no geomagnetic storm on the NOAA scale.

Measured
2026-09-17 03:00 UTC
Type
Published index
Provider
NOAA Space Weather Prediction Center

A planetary average over the three-hour interval beginning at the stated time.

Highest forecast Kp

3.67

Unsettled

NOAA's highest predicted three-hour Kp in the forecast window, for the interval beginning 2026-09-18 00:00 UTC. This is a forecast, not a measurement.

Kp: observed, estimated and predicted

Solid bars are observed intervals; dashed outlines are the interval in progress; hatched bars are NOAA's forecast.

0357909-1009-1109-1209-1309-1409-1509-1609-1709-1809-1909-20
  • Observed
  • Estimated
  • Predicted
  • Kp 5 or above (storm level)

Planetary K-index: 81 three-hour intervals, of which 64 are observed or estimated and 17 are NOAA forecasts. Highest observed planetary K-index 4.00, for the interval beginning 2026-09-14 15:00 UTC; no observed interval reaches storm level. Highest forecast planetary K-index 3.67, for the interval beginning 2026-09-18 00:00 UTC; no forecast interval reaches storm level.

Show these values as a table
Planetary K-index: 81 three-hour intervals, of which 64 are observed or estimated and 17 are NOAA forecasts. Highest observed planetary K-index 4.00, for the interval beginning 2026-09-14 15:00 UTC; no observed interval reaches storm level. Highest forecast planetary K-index 3.67, for the interval beginning 2026-09-18 00:00 UTC; no forecast interval reaches storm level.
Interval start (UTC)KpNOAA G-levelType
2026-09-10 00:00 UTC2.67—Observed
2026-09-10 03:00 UTC2.67—Observed
2026-09-10 06:00 UTC2.00—Observed
2026-09-10 09:00 UTC2.33—Observed
2026-09-10 12:00 UTC2.33—Observed
2026-09-10 15:00 UTC1.33—Observed
2026-09-10 18:00 UTC1.00—Observed
2026-09-10 21:00 UTC2.67—Observed
2026-09-11 00:00 UTC1.33—Observed
2026-09-11 03:00 UTC3.00—Observed
2026-09-11 06:00 UTC1.67—Observed
2026-09-11 09:00 UTC2.67—Observed
2026-09-11 12:00 UTC2.33—Observed
2026-09-11 15:00 UTC1.67—Observed
2026-09-11 18:00 UTC1.00—Observed
2026-09-11 21:00 UTC2.00—Observed
2026-09-12 00:00 UTC1.33—Observed
2026-09-12 03:00 UTC2.33—Observed
2026-09-12 06:00 UTC3.00—Observed
2026-09-12 09:00 UTC2.33—Observed
2026-09-12 12:00 UTC2.00—Observed
2026-09-12 15:00 UTC1.33—Observed
2026-09-12 18:00 UTC1.00—Observed
2026-09-12 21:00 UTC1.00—Observed
2026-09-13 00:00 UTC2.33—Observed
2026-09-13 03:00 UTC3.00—Observed
2026-09-13 06:00 UTC2.00—Observed
2026-09-13 09:00 UTC0.67—Observed
2026-09-13 12:00 UTC1.33—Observed
2026-09-13 15:00 UTC1.00—Observed
2026-09-13 18:00 UTC0.33—Observed
2026-09-13 21:00 UTC0.67—Observed
2026-09-14 00:00 UTC1.00—Observed
2026-09-14 03:00 UTC2.33—Observed
2026-09-14 06:00 UTC1.33—Observed
2026-09-14 09:00 UTC2.00—Observed
2026-09-14 12:00 UTC2.67—Observed
2026-09-14 15:00 UTC4.00—Observed
2026-09-14 18:00 UTC2.67—Observed
2026-09-14 21:00 UTC2.67—Observed
2026-09-15 00:00 UTC3.00—Observed
2026-09-15 03:00 UTC2.33—Observed
2026-09-15 06:00 UTC0.33—Observed
2026-09-15 09:00 UTC0.67—Observed
2026-09-15 12:00 UTC2.33—Observed
2026-09-15 15:00 UTC0.67—Observed
2026-09-15 18:00 UTC2.00—Observed
2026-09-15 21:00 UTC3.33—Observed
2026-09-16 00:00 UTC3.67—Observed
2026-09-16 03:00 UTC3.00—Observed
2026-09-16 06:00 UTC2.33—Observed
2026-09-16 09:00 UTC1.67—Observed
2026-09-16 12:00 UTC2.33—Observed
2026-09-16 15:00 UTC1.00—Observed
2026-09-16 18:00 UTC0.67—Observed
2026-09-16 21:00 UTC1.33—Observed
2026-09-17 00:00 UTC3.00—Observed
2026-09-17 03:00 UTC1.67—Observed
2026-09-17 06:00 UTC3.67—Estimated (interval in progress)
2026-09-17 09:00 UTC3.33—Estimated (interval in progress)
2026-09-17 12:00 UTC3.33—Estimated (interval in progress)
2026-09-17 15:00 UTC3.33—Estimated (interval in progress)
2026-09-17 18:00 UTC3.33—Estimated (interval in progress)
2026-09-17 21:00 UTC3.33—Estimated (interval in progress)
2026-09-18 00:00 UTC3.67—Predicted (forecast)
2026-09-18 03:00 UTC2.00—Predicted (forecast)
2026-09-18 06:00 UTC2.00—Predicted (forecast)
2026-09-18 09:00 UTC2.67—Predicted (forecast)
2026-09-18 12:00 UTC2.67—Predicted (forecast)
2026-09-18 15:00 UTC2.67—Predicted (forecast)
2026-09-18 18:00 UTC2.67—Predicted (forecast)
2026-09-18 21:00 UTC3.00—Predicted (forecast)
2026-09-19 00:00 UTC2.67—Predicted (forecast)
2026-09-19 03:00 UTC2.00—Predicted (forecast)
2026-09-19 06:00 UTC2.33—Predicted (forecast)
2026-09-19 09:00 UTC2.33—Predicted (forecast)
2026-09-19 12:00 UTC2.33—Predicted (forecast)
2026-09-19 15:00 UTC2.33—Predicted (forecast)
2026-09-19 18:00 UTC2.33—Predicted (forecast)
2026-09-19 21:00 UTC2.67—Predicted (forecast)
2026-09-20 00:00 UTC2.33—Predicted (forecast)

NOAA space weather scales

Live

  • Geomagnetic storms

    None

    Geomagnetic storms — disturbance of Earth's magnetic field, which drives aurora and can affect power grids, pipelines and satellite navigation.

  • Solar radiation storms

    None

    Solar radiation storms — elevated fluxes of energetic protons, which matter for spacecraft, high-altitude aviation on polar routes, and astronauts.

  • Radio blackouts

    None

    Radio blackouts — degradation of high-frequency radio communication on the sunlit side of Earth, caused by X-rays from a flare ionising the lower ionosphere.

Observed levels for 2026-09-17, stamped by NOAA at 2026-09-17 08:08 UTC. A level of zero means the threshold was genuinely not reached — it is a measurement, not a missing value.

NOAA's three-day forecast. These are predictions, not observations: the G column is an expected level and the R and S columns are probabilities.
DateGeomagnetic (G)Radio blackout ≥ R1Radiation storm
2026-09-17None expected5%1%
2026-09-18None expected5%1%
2026-09-19None expected5%1%

Watches, warnings and alerts

Live

No SWPC watch, warning or alert is inside its stated validity window right now. This is a real reading of the message stream, not an absence of data.

Recently issued messages (12)
  • EXTENDED WARNING: Geomagnetic K-index of 4 expected2026-09-16 05:38 UTC · expired
  • ALERT: Geomagnetic K-index of 42026-09-16 00:34 UTC
  • WARNING: Geomagnetic K-index of 5 expected2026-09-15 18:56 UTC · expired
  • WARNING: Geomagnetic K-index of 4 expected2026-09-15 18:50 UTC · expired
  • WATCH: Geomagnetic Storm Category G1 Predicted2026-09-15 17:37 UTC
  • ALERT: Geomagnetic K-index of 42026-09-14 18:02 UTC
  • WARNING: Geomagnetic K-index of 4 expected2026-09-14 16:54 UTC · expired
  • WATCH: Geomagnetic Storm Category G1 Predicted2026-09-14 15:47 UTC
  • Space weather message EF3A2026-09-14 11:03 UTC
  • Space weather message EF3A2026-09-13 08:27 UTC
  • Space weather message EF3A2026-09-12 06:45 UTC
  • Space weather message EF3A2026-09-11 05:01 UTC

X-ray flux and the current flare

Live

B2.1

Minor; no noticeable effects.

Reading taken
2026-09-17 08:04 UTC
Satellite
GOES-18
Event began
2026-09-16 11:46 UTC
Peak
2026-09-16 11:53 UTC · B3.4
Event ended
2026-09-16 12:03 UTC

Aurora forecast

Forecast

  • Northern hemisphere

    Computed by AsteriaStar

    Oval reaches 57° latitude

    The model's aurora oval extends to about 57° geographic latitude in this hemisphere, with a peak probability of 14% somewhere along it. That is a statement about the oval's extent, not about any particular place: whether aurora is actually visible from a given site also depends on cloud, darkness, light pollution and the northern horizon.

  • Southern hemisphere

    Computed by AsteriaStar

    Oval reaches 57° latitude

    The model's aurora oval extends to about 57° geographic latitude in this hemisphere, with a peak probability of 16% somewhere along it. That is a statement about the oval's extent, not about any particular place: whether aurora is actually visible from a given site also depends on cloud, darkness, light pollution and the northern horizon.

Derived from NOAA's OVATION grid by method equatorward-boundary/v1: the most equatorward latitude at which the model gives at least a 10% chance of visible aurora at any longitude, over all 65,160grid cells in the response. The computation is AsteriaStar's; the probabilities are NOAA's.

The model observation is from 2026-09-17 07:59 UTC and the forecast is valid for 2026-09-17 08:56 UTC. This says nothing about any particular place: cloud, moonlight, light pollution and your northern horizon are not in this dataset, and AsteriaStar will not guess at them.

Provenance

Every value on these pages is fetched from NOAA SWPC or NASA CCMC and carries the provider's own timestamp. Nothing is simulated, interpolated or filled in: when a provider cannot be reached, the panel says so and shows no number. There is no overall “space weather score” here — the agencies publish scales, and a single figure invented on top of them would be an opinion wearing NOAA's authority.

Solar wind speed

Live
Status
Live
Kind
Observation
Provider
NOAA Space Weather Prediction Center
Organisation
NOAA / National Weather Service
Fetched
2026-09-17 08:11 UTC
Generated by provider
2026-09-17 08:02 UTC
Provider cadence
1 min
Cached for
1 min
Treated as stale after
3 h
Licence
Public domain (US Government work). No licence fee and no redistribution restriction.

Source file: https://services.swpc.noaa.gov/products/summary/solar-wind-speed.json

Solar wind speed (real-time summary) from NOAA Space Weather Prediction Center, fetched from https://services.swpc.noaa.gov/products/summary/solar-wind-speed.json. The underlying spacecraft cadence is one minute, so a sixty-second cache can never hide a published value for longer than the interval between publications.

A single spot value from the real-time solar-wind monitor at the L1 Lagrange point, roughly 1.5 million km sunward of Earth — not a measurement at Earth. Solar wind takes on the order of an hour to cross that gap.

Planetary K-index

Recent
Status
Recent
Kind
Published index
Provider
NOAA Space Weather Prediction Center
Organisation
NOAA / National Weather Service
Fetched
2026-09-17 08:11 UTC
Generated by provider
2026-09-17 03:00 UTC
Provider cadence
3 h
Cached for
5 min
Treated as stale after
12 h
Licence
Public domain (US Government work). No licence fee and no redistribution restriction.

Source file: https://services.swpc.noaa.gov/products/noaa-planetary-k-index.json

Planetary K-index (observed) from NOAA Space Weather Prediction Center, fetched from https://services.swpc.noaa.gov/products/noaa-planetary-k-index.json. Kp is defined over three-hour intervals, so a five-minute cache is two orders of magnitude finer than the quantity's own resolution.

A planetary average over three hours from a network of magnetometer stations. It says nothing about conditions at one location, and a quiet Kp does not rule out a local disturbance.

NOAA scales

Live
Status
Live
Kind
Published index
Provider
NOAA Space Weather Prediction Center
Organisation
NOAA / National Weather Service
Fetched
2026-09-17 08:11 UTC
Generated by provider
2026-09-17 08:08 UTC
Provider cadence
30 min
Cached for
5 min
Treated as stale after
6 h
Licence
Public domain (US Government work). No licence fee and no redistribution restriction.

Source file: https://services.swpc.noaa.gov/products/noaa-scales.json

NOAA space weather scales (R, S, G) from NOAA Space Weather Prediction Center, fetched from https://services.swpc.noaa.gov/products/noaa-scales.json. SWPC regenerates the scales roughly every half hour; a five-minute cache cannot delay a change by a meaningful fraction of that.

The R (radio blackout), S (solar radiation) and G (geomagnetic) scales summarise the last 24 hours and the next three days. The forecast entries are probabilities and expected levels, not observations.

Aurora forecast

Forecast
Status
Forecast
Kind
Forecast
Provider
NOAA Space Weather Prediction Center
Organisation
NOAA / National Weather Service
Fetched
2026-09-17 08:11 UTC
Generated by provider
2026-09-17 07:59 UTC
Provider cadence
5 min
Cached for
10 min
Treated as stale after
6 h
Licence
Public domain (US Government work). No licence fee and no redistribution restriction.

Source file: https://services.swpc.noaa.gov/json/ovation_aurora_latest.json

OVATION aurora forecast grid from NOAA Space Weather Prediction Center, fetched from https://services.swpc.noaa.gov/json/ovation_aurora_latest.json. The OVATION grid is roughly a megabyte and is regenerated every five minutes for a forecast valid about an hour ahead; a ten-minute cache is a small fraction of the forecast's own validity window and keeps a page view from costing a megabyte of transfer.

A model FORECAST of the probability of visible aurora on a one-degree grid, valid for a time about an hour ahead of the observation it is derived from. It is not a measurement, it is not a cloud forecast, and a high probability at your latitude does not mean the sky above you is clear.

Sources & references

The primary and reference sources this topic draws on.

  • NOAA SWPCNOAA Space Weather Prediction Center

    Space-weather forecasts and alerts: aurora (OVATION), the Kp index, and the G1–G5 geomagnetic storm scale.

  • NASA DONKINASA Community Coordinated Modeling Center

    The Space Weather Database Of Notifications, Knowledge, Information: solar flares, CMEs, and geomagnetic storms.