Aurora
Where the auroral oval reaches, according to NOAA's model — and, just as importantly, what that does and does not tell you about whether you will see anything.
Aurora forecast
ForecastNorthern hemisphere
Computed by AsteriaStarOval reaches 55° latitude
The model's aurora oval extends to about 55° 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 AsteriaStarOval reaches 64° latitude
The model's aurora oval extends to about 64° 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 05:30 UTC and the forecast is valid for 2026-09-17 06:26 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.
The index behind the oval
The auroral oval widens and pushes equatorward as geomagnetic activity rises, which is why the planetary K-index is the number aurora watchers follow. It is a three-hourly planetary average, so it describes the global state, not your sky.
Latest observed Kp
Recent3
Unsettled
Unsettled; aurora possible at high latitudes. Below Kp 5 there is no geomagnetic storm on the NOAA scale.
- Measured
- 2026-09-17 00:00 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
For the interval beginning 2026-09-18 00:00 UTC. A NOAA forecast, not an observation.
- Observed
- Estimated
- Predicted
- Kp 5 or above (storm level)
Planetary K-index for aurora watching: 81 three-hour intervals, of which 64 are observed or estimated and 17 are NOAA forecasts. Highest observed planetary K-index 4.67, for the interval beginning 2026-09-17 03:00 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
| Interval start (UTC) | Kp | NOAA G-level | Type |
|---|---|---|---|
| 2026-09-10 00:00 UTC | 2.67 | — | Observed |
| 2026-09-10 03:00 UTC | 2.67 | — | Observed |
| 2026-09-10 06:00 UTC | 2.00 | — | Observed |
| 2026-09-10 09:00 UTC | 2.33 | — | Observed |
| 2026-09-10 12:00 UTC | 2.33 | — | Observed |
| 2026-09-10 15:00 UTC | 1.33 | — | Observed |
| 2026-09-10 18:00 UTC | 1.00 | — | Observed |
| 2026-09-10 21:00 UTC | 2.67 | — | Observed |
| 2026-09-11 00:00 UTC | 1.33 | — | Observed |
| 2026-09-11 03:00 UTC | 3.00 | — | Observed |
| 2026-09-11 06:00 UTC | 1.67 | — | Observed |
| 2026-09-11 09:00 UTC | 2.67 | — | Observed |
| 2026-09-11 12:00 UTC | 2.33 | — | Observed |
| 2026-09-11 15:00 UTC | 1.67 | — | Observed |
| 2026-09-11 18:00 UTC | 1.00 | — | Observed |
| 2026-09-11 21:00 UTC | 2.00 | — | Observed |
| 2026-09-12 00:00 UTC | 1.33 | — | Observed |
| 2026-09-12 03:00 UTC | 2.33 | — | Observed |
| 2026-09-12 06:00 UTC | 3.00 | — | Observed |
| 2026-09-12 09:00 UTC | 2.33 | — | Observed |
| 2026-09-12 12:00 UTC | 2.00 | — | Observed |
| 2026-09-12 15:00 UTC | 1.33 | — | Observed |
| 2026-09-12 18:00 UTC | 1.00 | — | Observed |
| 2026-09-12 21:00 UTC | 1.00 | — | Observed |
| 2026-09-13 00:00 UTC | 2.33 | — | Observed |
| 2026-09-13 03:00 UTC | 3.00 | — | Observed |
| 2026-09-13 06:00 UTC | 2.00 | — | Observed |
| 2026-09-13 09:00 UTC | 0.67 | — | Observed |
| 2026-09-13 12:00 UTC | 1.33 | — | Observed |
| 2026-09-13 15:00 UTC | 1.00 | — | Observed |
| 2026-09-13 18:00 UTC | 0.33 | — | Observed |
| 2026-09-13 21:00 UTC | 0.67 | — | Observed |
| 2026-09-14 00:00 UTC | 1.00 | — | Observed |
| 2026-09-14 03:00 UTC | 2.33 | — | Observed |
| 2026-09-14 06:00 UTC | 1.33 | — | Observed |
| 2026-09-14 09:00 UTC | 2.00 | — | Observed |
| 2026-09-14 12:00 UTC | 2.67 | — | Observed |
| 2026-09-14 15:00 UTC | 4.00 | — | Observed |
| 2026-09-14 18:00 UTC | 2.67 | — | Observed |
| 2026-09-14 21:00 UTC | 2.67 | — | Observed |
| 2026-09-15 00:00 UTC | 3.00 | — | Observed |
| 2026-09-15 03:00 UTC | 2.33 | — | Observed |
| 2026-09-15 06:00 UTC | 0.33 | — | Observed |
| 2026-09-15 09:00 UTC | 0.67 | — | Observed |
| 2026-09-15 12:00 UTC | 2.33 | — | Observed |
| 2026-09-15 15:00 UTC | 0.67 | — | Observed |
| 2026-09-15 18:00 UTC | 2.00 | — | Observed |
| 2026-09-15 21:00 UTC | 3.33 | — | Observed |
| 2026-09-16 00:00 UTC | 3.67 | — | Observed |
| 2026-09-16 03:00 UTC | 3.00 | — | Observed |
| 2026-09-16 06:00 UTC | 2.33 | — | Observed |
| 2026-09-16 09:00 UTC | 1.67 | — | Observed |
| 2026-09-16 12:00 UTC | 2.33 | — | Observed |
| 2026-09-16 15:00 UTC | 1.00 | — | Observed |
| 2026-09-16 18:00 UTC | 0.67 | — | Observed |
| 2026-09-16 21:00 UTC | 1.33 | — | Observed |
| 2026-09-17 00:00 UTC | 3.00 | — | Observed |
| 2026-09-17 03:00 UTC | 4.67 | — | Estimated (interval in progress) |
| 2026-09-17 06:00 UTC | 3.67 | — | Estimated (interval in progress) |
| 2026-09-17 09:00 UTC | 3.33 | — | Estimated (interval in progress) |
| 2026-09-17 12:00 UTC | 3.33 | — | Estimated (interval in progress) |
| 2026-09-17 15:00 UTC | 3.33 | — | Estimated (interval in progress) |
| 2026-09-17 18:00 UTC | 3.33 | — | Estimated (interval in progress) |
| 2026-09-17 21:00 UTC | 3.33 | — | Estimated (interval in progress) |
| 2026-09-18 00:00 UTC | 3.67 | — | Predicted (forecast) |
| 2026-09-18 03:00 UTC | 2.00 | — | Predicted (forecast) |
| 2026-09-18 06:00 UTC | 2.00 | — | Predicted (forecast) |
| 2026-09-18 09:00 UTC | 2.67 | — | Predicted (forecast) |
| 2026-09-18 12:00 UTC | 2.67 | — | Predicted (forecast) |
| 2026-09-18 15:00 UTC | 2.67 | — | Predicted (forecast) |
| 2026-09-18 18:00 UTC | 2.67 | — | Predicted (forecast) |
| 2026-09-18 21:00 UTC | 3.00 | — | Predicted (forecast) |
| 2026-09-19 00:00 UTC | 2.67 | — | Predicted (forecast) |
| 2026-09-19 03:00 UTC | 2.00 | — | Predicted (forecast) |
| 2026-09-19 06:00 UTC | 2.33 | — | Predicted (forecast) |
| 2026-09-19 09:00 UTC | 2.33 | — | Predicted (forecast) |
| 2026-09-19 12:00 UTC | 2.33 | — | Predicted (forecast) |
| 2026-09-19 15:00 UTC | 2.33 | — | Predicted (forecast) |
| 2026-09-19 18:00 UTC | 2.33 | — | Predicted (forecast) |
| 2026-09-19 21:00 UTC | 2.67 | — | Predicted (forecast) |
| 2026-09-20 00:00 UTC | 2.33 | — | Predicted (forecast) |
What makes an aurora
Aurorae occur when charged particles from the Sun — carried by the solar wind and coronal mass ejections — are funnelled by Earth's magnetic field into the upper atmosphere, exciting oxygen and nitrogen to glow.
OVATION estimates the flux of precipitating particles from the solar-wind conditions measured upstream at L1, and turns that into a probability of visible aurora on a grid covering both hemispheres. Because it is driven by an upstream measurement, it is a genuine forecast — typically about an hour ahead — rather than a nowcast.
What this page will not tell you
It will not tell you whether you will see the aurora tonight from where you live. That question needs four things this dataset does not contain: whether the sky above you is clear, how dark it is where you are, how much light pollution sits on your northern horizon, and whether the Moon is up. Two of those are answerable elsewhere on this platform — the Tonight planner works out the darkness and the Moon for coordinates you type, and will fetch a cloud-cover forecast if you ask it to. Light pollution is not connected to anything here, and none of it is guessed at.
What it does tell you is real and useful: how far the oval currently reaches, how strong the model thinks it is, and what the geomagnetic index is doing. If the oval is nowhere near your latitude, the weather does not matter. If it is, cloud cover is the next thing to check, and the Tonight planner will fetch it from MET Norway on request — from your own browser, so your location never reaches this site.
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.
OVATION aurora forecast
Forecast- Status
- Forecast
- Kind
- Forecast
- Provider
- NOAA Space Weather Prediction Center
- Organisation
- NOAA / National Weather Service
- Fetched
- 2026-09-17 05:41 UTC
- Generated by provider
- 2026-09-17 05:30 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.
Observed Kp
Recent- Status
- Recent
- Kind
- Published index
- Provider
- NOAA Space Weather Prediction Center
- Organisation
- NOAA / National Weather Service
- Fetched
- 2026-09-17 05:41 UTC
- Generated by provider
- 2026-09-17 00:00 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.
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.