Forecast result
Your aurora score and viewing window will appear here.
Forecast summary
Score breakdown
Tonight's sky and viewing guidance
- Sunset
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- Astronomical twilight ends
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- Sunrise
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- Moonrise / moonset
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- Temperature / humidity
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- Rain chance / local wind
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- Horizon advice
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- Travel direction
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Photography guidance
Viewing checklist
Hourly viewing forecast
| Date | Time | Kp | Cloud | Moon | Darkness | Aurora chance | Score |
|---|
Check a location
Search a place or enter coordinates manually.
How the Northern Lights Forecast Checker Works
This checker combines space weather with local sky conditions. The planetary Kp index describes global geomagnetic activity. Higher Kp values can push visible aurora farther from polar regions. Latitude still matters because the auroral oval usually favors high northern locations. The tool therefore compares Kp with your selected latitude. It also reads the nearest NOAA aurora oval grid value when available. That grid value helps describe current modeled auroral activity near the location.
Weather and darkness matter too
Strong aurora can remain invisible behind thick clouds. Hourly cloud cover therefore contributes heavily to the viewing score. Darkness is calculated from local sunset and sunrise information. The strongest viewing hours are normally during true night. Moonlight can reduce contrast when the aurora is faint. The checker uses moon phase and illumination to adjust that part of the score. Fog codes, precipitation probability, humidity, wind, and temperature provide extra planning context. These conditions do not create aurora, but they influence practical visibility and comfort. Clear air and low cloud percentages generally provide the strongest observing opportunity. Wind and temperature also help visitors prepare suitable clothing and equipment.
Reading the final score
The overall score combines geomagnetic activity, clouds, darkness, and moonlight. It is a planning estimate rather than a guarantee. Solar wind speed and southward IMF Bz are also displayed. Faster solar wind and negative Bz can support stronger geomagnetic responses. The best viewing window ranks available nighttime hours using forecast conditions. For locations below common auroral latitudes, a clear northern horizon becomes more important. Traveling away from city lights can also improve contrast. A tripod and wide lens help cameras capture faint structure. Forecasts change quickly during active solar events. Refresh the checker before leaving for your viewing location. Compare several nearby hours instead of relying on one isolated score. Sudden solar-wind changes can improve conditions after the original forecast was issued.
Example viewing guide
| Kp range | General activity | Typical planning note |
|---|---|---|
| 0–2 | Quiet | Best suited to high auroral latitudes. |
| 3–4 | Unsettled to active | Good northern viewing may occur under clear skies. |
| 5–6 | Geomagnetic storm | Aurora can expand toward lower latitudes. |
| 7–9 | Strong to extreme storm | Unusual lower-latitude sightings become more possible. |
Latitude guidance is approximate because geographic latitude differs from geomagnetic latitude.
Frequently Asked Questions
What Kp index is good for Northern Lights?
There is no single universal value. High-latitude locations can see aurora at low Kp, while lower latitudes usually require stronger geomagnetic activity.
Does cloud cover affect the aurora itself?
No. Clouds do not stop auroral activity, but they can completely block your view from the ground.
Why is southward Bz useful?
A negative or southward IMF Bz can couple more effectively with Earth's magnetic field, supporting stronger geomagnetic responses when other conditions cooperate.
Can I use the seven-day option for Kp?
The interface can show seven days of local weather. NOAA's detailed Kp forecast has a shorter horizon, so later rows may show Kp as unavailable.
Is the overall score a guarantee?
No. It is a planning score built from forecast data and simple heuristics. Aurora can brighten or fade rapidly.
Where do the data come from?
Space-weather values come from NOAA's Space Weather Prediction Center. Local weather and astronomical fields come from Open-Meteo.