# Lumavik

> Lumavik publishes aurora forecasting explainers, free space-weather tools that run
> entirely in the browser, and the Lumavik aurora forecast app for iPhone. The site
> answers one question in as many honest ways as it can: what a given place needs
> before the northern lights are worth looking for, and why most nights the answer
> is no.

Three things have to be true at once for an aurora to be seen: the observer has to be
close enough to the auroral oval in GEOMAGNETIC latitude (not map latitude), geomagnetic
activity has to be high enough to bring the oval to them, and the sky has to be
astronomically dark. Above about 60 degrees the third constraint closes the season for
months at a time and no Kp value reopens it. Cloud beats all three.

Nothing on this site is a live reading. Current conditions come from NOAA SWPC, whose
endpoints are keyless and CORS-open and are listed at https://lumavik.org/api/v1/sources.json

Published by Vast Flow, LLP. Editorial policy and who writes this: https://lumavik.org/about/
Reuse: CC BY 4.0 with a link back.

## For machines

- [API documentation](https://lumavik.org/api/): what each dataset contains and what each field means
- [OpenAPI 3.1 description](https://lumavik.org/api/v1/openapi.json)
- [Visibility thresholds](https://lumavik.org/api/v1/visibility.json): the oval edge at each Kp, the NOAA storm scale, the viewing bands
- [Locations](https://lumavik.org/api/v1/cities.json): 14 places, both Kp thresholds, solstice darkness
- [Darkness and season](https://lumavik.org/api/v1/darkness.json): astronomical darkness by latitude and month, plus the camera model
- [Glossary](https://lumavik.org/api/v1/glossary.json): one self-contained definition per term
- [Sources and live feeds](https://lumavik.org/api/v1/sources.json): 41 primary sources and the NOAA endpoints this site reads
- [Status](https://lumavik.org/api/v1/status.json): when each dataset was rebuilt
- [Agent skills](https://lumavik.org/.well-known/agent-skills/index.json): four SKILL.md documents on reading this data correctly
- [MCP server](https://lumavik.org/mcp): seven read-only tools · card at https://lumavik.org/.well-known/mcp/server-card.json
- [A2A endpoint](https://lumavik.org/a2a): card at https://lumavik.org/.well-known/agent-card.json
- [Agent access policy](https://lumavik.org/auth.md): there is no authentication and none is possible
- [Full text of the primary pages](https://lumavik.org/llms-full.txt)
- Every page has a markdown twin at `<path>/index.md`, also served on `Accept: text/markdown`.

## Free tools — they run in your browser, nothing is sent anywhere

- [Aurora camera settings calculator](https://lumavik.org/tools/aurora-camera-settings/): aurora camera settings calculator
- [Can I see the aurora tonight from where I am?](https://lumavik.org/tools/can-i-see-the-aurora-tonight/): can I see the aurora tonight
- [Dark hours calculator: the aurora-season calendar by latitude](https://lumavik.org/tools/dark-hours-calendar/): dark hours calculator
- [Geomagnetic Latitude Calculator and Kp Thresholds](https://lumavik.org/tools/geomagnetic-latitude-calculator/): geomagnetic latitude calculator
- [Live aurora forecast: current Kp and the NOAA 3-day outlook](https://lumavik.org/tools/aurora-forecast/): live aurora forecast

## Reference layer — written to be quoted in isolation

- [Aurora forms and names: what you are looking at](https://lumavik.org/skywatch/aurora-forms-and-names/): What is the thing in the sky called?
- [Aurora glossary: the space-weather terms defined](https://lumavik.org/skywatch/aurora-glossary/): What does this space-weather term mean?
- [Geomagnetic indices explained, side by side](https://lumavik.org/skywatch/geomagnetic-indices-explained/): Kp, ap, Dst, AE or Hp30 — which number should I be reading?
- [Geomagnetic storm effects: what happens besides aurora](https://lumavik.org/skywatch/geomagnetic-storm-effects/): What does a geomagnetic storm do besides make aurora?
- [Moon phase and aurora visibility: when the Moon matters](https://lumavik.org/skywatch/moon-phase-and-aurora-visibility/): Does the Moon ruin an aurora night?
- [Solar Cycle 25 and the aurora: a dated timeline](https://lumavik.org/skywatch/solar-cycle-25-and-the-aurora/): Has solar maximum passed, and does that end the good years?
- [The auroral substorm: why a quiet arc suddenly explodes](https://lumavik.org/skywatch/auroral-substorm-explained/): Why does the aurora suddenly erupt and then fade?
- [What an aurora alert cannot do, including ours](https://lumavik.org/skywatch/what-aurora-alerts-cannot-do/): Can an aurora alert actually promise me a sighting?
- [Where aurora forecast data comes from: the instruments](https://lumavik.org/skywatch/where-aurora-data-comes-from/): Where does aurora forecast data actually come from?
- [Why you did not see the aurora, by symptom](https://lumavik.org/skywatch/why-you-did-not-see-the-aurora/): The forecast was good and I saw nothing. What went wrong?

## Explainers

- [Aurora australis southern lights: a harder geography](https://lumavik.org/skywatch/aurora-australis-southern-lights/): aurora australis southern lights
- [Aurora Oval Explained: Why the Lights Form a Ring, Not a Cap](https://lumavik.org/skywatch/aurora-oval-explained/): aurora oval explained
- [Best Aurora Forecast App: An Honest Comparison](https://lumavik.org/skywatch/aurora-forecast-apps/): best aurora forecast app
- [Best Time to See the Northern Lights: A Practical Guide](https://lumavik.org/skywatch/best-time-to-see-northern-lights/): best time to see the northern lights
- [Geomagnetic latitude aurora: why your neighbour sees more aurora](https://lumavik.org/skywatch/geomagnetic-latitude-and-aurora/): geomagnetic latitude aurora
- [How accurate is the aurora forecast, really?](https://lumavik.org/skywatch/aurora-forecast-accuracy/): how accurate is the aurora forecast
- [How to photograph the northern lights with a phone](https://lumavik.org/skywatch/photograph-the-aurora-with-a-phone/): how to photograph the northern lights with a phone
- [How to read the OVATION aurora model honestly](https://lumavik.org/skywatch/ovation-aurora-model/): OVATION aurora model
- [Kp index explained, and what it cannot tell you](https://lumavik.org/skywatch/kp-index-explained/): Kp index explained
- [Northern lights photography settings that adapt](https://lumavik.org/skywatch/northern-lights-photography-settings/): northern lights photography settings
- [Northern Lights Season: Why Darkness Matters](https://lumavik.org/skywatch/northern-lights-season/): northern lights season
- [Solar Wind Aurora Forecast: Read Bz, Speed and Density](https://lumavik.org/skywatch/solar-wind-and-aurora/): solar wind aurora forecast
- [What Kp index to see the northern lights: the answer by location](https://lumavik.org/skywatch/what-kp-index-to-see-northern-lights/): what Kp index to see the northern lights
- [Why is the aurora green?](https://lumavik.org/skywatch/why-is-the-aurora-green/): why is the aurora green

## The app, compared with the alternatives

- [Lumavik for iPhone](https://lumavik.org/): chance-tonight score, live Kp, the OVATION oval map, push alerts
- [Lumavik vs Aurora Forecast & Alerts](https://lumavik.org/compare/lumavik-vs-aurora-forecast-and-alerts/)
- [Lumavik vs Aurora Forecast.: Which Aurora App Fits You?](https://lumavik.org/compare/lumavik-vs-aurora-forecast/)
- [Lumavik vs Aurora Now - Northern Lights](https://lumavik.org/compare/lumavik-vs-aurora-now-northern-lights/)
- [Lumavik vs AuroraWatch UK Aurora Alerts](https://lumavik.org/compare/lumavik-vs-aurorawatch-uk-aurora-alerts/)
- [Lumavik vs My Aurora Forecast & Alerts](https://lumavik.org/compare/lumavik-vs-my-aurora-forecast-and-alerts/)
- [Lumavik vs SpaceWeatherLive](https://lumavik.org/compare/lumavik-vs-spaceweatherlive/)

## About and policy

- [About](https://lumavik.org/about/): who writes this and what the site will not claim
- [Contact](https://lumavik.org/contact/)
- [Privacy](https://lumavik.org/privacy/)
- [Terms](https://lumavik.org/terms/)

Generated: 2026-09-11