Aurora Nowcast adapter for ioBroker
Provides current (nowcast) data on aurora activity (northern and southern lights) for a given location, based on publicly available data from the NOAA Space Weather Prediction Center (SWPC).
Note:
The OVATION aurora data represents current conditions (nowcast) based on real-time solar wind measurements — not a long-range forecast.
The Kp index feed additionally provides a 72-hour forecast for planning purposes.
Features
- Retrieves real-time aurora activity data (NOAA OVATION model) for both northern and southern hemisphere
- Calculates local aurora visibility likelihood for a configured location
- Provides current Kp index (1-minute feed) and a 72-hour Kp forecast
- Provides real-time solar wind data (Bz, total field, speed, density) as aurora early-warning indicators
- Provides ioBroker states for automation, visualization and alerts
- Optional usage of system location or manual latitude/longitude input
- Suitable for dashboards, notifications and smart home scenarios
❤️ Support
If you find ioBroker.aurora-nowcast useful and would like to support further development, you might want to buy me a coffee. ☕🙂
Thank you for your support!
Configuration
You can either:
- Use the system location configured in ioBroker, or
- Provide manual coordinates (latitude / longitude in decimal degrees)
Manual coordinates are required if system location is disabled.
Examples:
| Location | Latitude | Longitude |
|---|---|---|
| Berlin | 52.5 | 13.4 |
| Buenos Aires | -34.6 | -58.4 |
| Reykjavik | 64.1 | -21.9 |
North/East values are positive, South/West values are negative.
Update Intervals
| Setting | Default | Range | Description |
|---|---|---|---|
| Standard interval | 5 | 1–60 | How often OVATION aurora data, Kp forecast and storm scales are fetched (minutes) |
| Realtime interval | 1 | 1–60 | How often realtime feeds are fetched: current Kp index, solar wind (minutes) |
States
Background: Space Weather Indices
Kp index — The planetary K index measures global geomagnetic activity on a scale of 0–9 (0 = quiet, 9 = extreme storm). Values ≥ 5 indicate geomagnetic storm conditions (G1 and above), under which aurora becomes visible at mid-latitudes such as Central Europe. The adapter provides both the current 1-minute Kp reading and a 72-hour forecast.
OVATION — Aurora probability
| State | Type | Description |
|---|---|---|
probability | number | Estimated aurora visibility probability at the configured location (%) |
observation_time | number | Time of the upstream solar wind observation used as model input (UTC, ms) |
forecast_time | number | Time for which the nowcasted geomagnetic response at Earth is calculated (UTC, ms) |
Kp index
| State | Type | Description |
|---|---|---|
kp.value | number | Current Kp index (0–9, decimal, 1-minute feed) |
kp.time | number | Measurement time of the current Kp value (UTC, ms) |
kp.g_scale | number | Derived NOAA G-scale (0 = none, 1–5 = G1–G5) |
kp.forecast_max | number | Maximum Kp value in the 72-hour forecast |
kp.forecast_max_time | number | Time at which the forecast maximum occurs (UTC, ms) |
kp.forecast | string | Full 72-hour Kp forecast as JSON array [{time, kp}] |
Solar wind
Bz (GSM) — The z-component of the interplanetary magnetic field in GSM coordinates. A strongly negative Bz (southward orientation) opens the Earth's magnetosphere to incoming solar wind energy and is the most reliable short-term aurora precursor — typically 15–60 minutes ahead of visible activity. Bt is the total field magnitude; Bz relative to Bt indicates how strongly southward the field is oriented.
| State | Type | Unit | Description |
|---|---|---|---|
solar_wind.bz | number | nT | Bz component in GSM coordinates (negative = southward) |
solar_wind.bt | number | nT | Total interplanetary magnetic field strength |
solar_wind.speed | number | km/s | Solar wind proton speed |
solar_wind.density | number | p/cm³ | Solar wind proton density |
solar_wind.mag_time | number | ms | Magnetometer measurement time (UTC) |
solar_wind.plasma_time | number | ms | Plasma measurement time (UTC) |
These states can be used for:
- Notifications (e.g. push messages when Kp ≥ 5 or Bz ≤ −10 nT)
- Dashboard visualizations
- Automation rules (e.g. activate camera when aurora probability is high)
Practical guide: catching the aurora
Aurora chasing works in two stages: planning ahead using the Kp forecast, and reacting in real time using solar wind and OVATION data.
Stage 1 — Plan: is a storm expected?
Use kp.forecast_max to check whether a geomagnetic storm is expected in the next 72 hours. Rough visibility thresholds by geographic latitude:
kp.forecast_max | Storm level | Visible down to ~ |
|---|---|---|
| < 5 | None | High latitudes only |
| 5 (G1) | Minor | ~60°N — northern Scotland, southern Scandinavia |
| 6 (G2) | Moderate | ~55°N — northern Germany, Poland |
| 7 (G3) | Strong | ~50°N — London, Frankfurt, Warsaw |
| 8 (G4) | Severe | ~45°N — Switzerland, Austria, northern Italy |
| 9 (G5) | Extreme | ~40°N — central France, northern Spain |
kp.forecast_max_time tells you when the peak is expected — useful for a notification like "G2 storm forecast for tonight."
kp.g_scale reflects the current storm level in real time (0 = quiet, 1–5 = G1–G5).
Note: These are approximate geographic latitudes for Europe. Actual visibility depends strongly on
solar_wind.bz(see below), cloud cover, and light pollution.
Stage 2 — React: is aurora active right now?
Even with a high Kp, aurora only becomes visible when the interplanetary magnetic field (IMF) turns southward — shown by a strongly negative solar_wind.bz. This is the most reliable short-term trigger.
solar_wind.bz | Meaning |
|---|---|
| > 0 nT | Northward — magnetosphere largely closed, little aurora |
| 0 to −5 nT | Weakly southward — marginal conditions |
| −5 to −10 nT | Southward — aurora activity begins to build |
| ≤ −10 nT | Strongly southward — significant aurora likely |
| ≤ −20 nT | Extreme — intense aurora well into mid-latitudes |
Lead time: Bz is measured at the L1 observation point between Earth and Sun. The solar wind takes 15–60 minutes to travel from L1 to Earth — this is your warning window.
solar_wind.bt is the total field strength. When |bz| approaches bt, the field is nearly fully southward. For example, bz = −18 nT with bt = 20 nT is a stronger signal than bz = −10 nT with bt = 30 nT.
solar_wind.speed amplifies the effect: fast wind (> 400 km/s) combined with negative Bz delivers more energy to the magnetosphere. Very high speeds (> 600 km/s) can drive aurora even with moderate Bz.
solar_wind.density plays a supporting role: high density (> 10 p/cm³) increases dynamic pressure and can enhance activity.
Location-specific confirmation: what does probability add?
Kp is a global index — it describes overall geomagnetic activity, not what is happening above your location. probability is different: it is calculated specifically for your configured coordinates using the NOAA OVATION model, which takes real-time solar wind measurements as direct input and models the actual extent and intensity of the aurora oval. It therefore reacts faster and more precisely to changes in Bz than the derived Kp value.
For Central Europe (around 50–55°N), realistic ranges during active conditions:
probability | Interpretation |
|---|---|
| < 5 % | No meaningful activity at your location |
| 5–15 % | Elevated — worth watching, especially away from cities |
| 15–30 % | Active — aurora likely visible if skies are clear |
| > 30 % | Strong activity overhead |
Use probability as the location-specific confirmation on top of Kp and Bz. A rising value alongside a strongly negative Bz is the clearest sign that it is worth going outside.
Example automation logic
A practical three-layer alert strategy:
- Watch mode —
kp.forecast_max≥ 5: "Storm expected in the next 72 hours — monitor conditions tonight" - Alert —
kp.value≥ 5 ANDsolar_wind.bz≤ −10: "Storm active and Bz strongly southward — aurora likely in 15–60 minutes" - Overhead confirmation —
probability≥ 15: "Aurora likely visible at your location right now"
Combining all three layers avoids false alarms: the Kp filter confirms a real storm, the Bz filter confirms the magnetosphere is open, and the probability filter confirms activity at your exact location.
Data Source
This adapter uses publicly available data provided by the:
- NOAA Space Weather Prediction Center (SWPC)
https://www.swpc.noaa.gov/
In particular, the OVATION aurora nowcast model and related real-time geomagnetic indices are used to estimate auroral activity for the configured location.
Disclaimer
NOAA and SWPC are not affiliated with this project.
The data used by this adapter is provided by NOAA for public use.
No guarantee is made regarding the accuracy, completeness or timeliness of the provided information.
Aurora visibility depends on multiple external factors (e.g. cloud cover, light pollution, IMF orientation) which are beyond the scope of this adapter.
Changelog
WORK IN PROGRESS
- when upgrading from version 2.2.2 or earlier to version 2.3.0 or later, any instance should be manually deleted and recreated. Otherwise they will remain registered as CRON-type adapters. As the datapoints don't include any IDs or other dynamic values, they will be recreated exactly as they were and no script adjustments will be necessary.
- fixed issue (https://github.com/chrmenne/ioBroker.aurora-nowcast/issues/38)
- fixed issue (https://github.com/chrmenne/ioBroker.aurora-nowcast/issues/37)
2.3.0 (2026-06-19)
- added solar wind data: Bz, total field (Bt), proton speed and density as aurora early-warning indicators
- added Kp index: current value (1-minute feed) and 72-hour forecast with maximum detection
- added separate realtime polling interval for time-critical feeds (Kp, solar wind)
- switched from single-run to continuous interval-based polling (daemon mode)
- configurable update interval (1–60 minutes, default: 5)
- fixed issue (https://github.com/chrmenne/ioBroker.aurora-nowcast/issues/32)
- fixed issue (https://github.com/chrmenne/ioBroker.aurora-nowcast/issues/33)
- fixed issue (https://github.com/chrmenne/ioBroker.aurora-nowcast/issues/35)
2.2.2 (2026-04-17)
- re-added git-type URL because of npm linter
2.2.1 (2026-04-17)
- more checks
- fixed Readme link to a more stable direct link instead of an anchor
- fixed issue (https://github.com/chrmenne/ioBroker.aurora-nowcast/issues/24)
- fixed issue (https://github.com/chrmenne/ioBroker.aurora-nowcast/issues/27)
2.2.0 (2026-03-30)
- fixed review findings (https://github.com/chrmenne/ioBroker.aurora-nowcast/issues/21)
2.1.4 (2026-03-11)
- disabled Sentry in GitHub workflow
License
GNU General Public License v3.0
Copyright (c) 2026 Christian Menne
See LICENSE file for full license text.