Aurora Forecast Tonight in Trondheim
Aurora season in Trondheim runs from September to April.
Tonight's Forecast
Low
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How we calculate the aurora score
LowWe combine geomagnetic activity (Kp), aurora oval probability (OVATION), cloud cover, darkness and moonlight, weighted for Trondheim (region: mid_latitude).
Score 0–19. Conditions strongly limit aurora visibility.
Score 20–44. A faint aurora is possible only under perfect conditions.
Score 45–64. Aurora may be visible to alert observers in dark, clear skies.
Score 65–84. A good chance of a visible aurora display.
Score 85–100. Excellent odds — plan to be outside tonight.
Low chance tonight. Aurora may be possible only under very favorable local conditions.
Skies may be clear in Trondheim, but aurora activity is currently too weak for a good viewing chance.
Max Kp
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Max Kp
Near thresholdKp is close to the minimum needed — a faint aurora may appear low on the horizon.
3.0
Near threshold
Cloud Cover
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Cloud Cover
Clear skiesUp to 25% cloud — excellent visibility.
1%
Clear skies
Moon
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Moon
Bright moonOver 75% illuminated — only strong displays will be visible.
88%
Bright moon
OVATION
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OVATION
Moderate5–20% probability — aurora possible.
9%
Moderate
Best Viewing Window
1:00 AM – 3:00 AM
Best balance of darkness, geomagnetic activity and local sky conditions.
Direction to Look
North
At this latitude, aurora is usually seen toward the northern horizon.
Recommendation
Check the forecast again later. Aurora conditions can change quickly during geomagnetic activity.
Hour-by-hour visibility
Estimated aurora visibility score for each hour of tonight at Trondheim.
12:00 AM
25/100Max Kp
2.0
Cloud Cover
12%
Moon
88%
OVATION
9%
49
1:00 AM
49/100Max Kp
3.0
Cloud Cover
2%
Moon
88%
OVATION
9%
31
2:00 AM
31/100Max Kp
3.0
Cloud Cover
0%
Moon
88%
OVATION
9%
3:00 AM
31/100Max Kp
3.0
Cloud Cover
1%
Moon
88%
OVATION
9%
4:00 AM
12/1004:00 AM: 12/100 — unlikely
Max Kp
3.0
Cloud Cover
2%
Moon
88%
OVATION
9%
Best viewing window: 1:00 AM – 3:00 AM. Peak around 1:00 AM with a visibility score of 49/100.
Why this forecast?
There is a low chance of visible aurora tonight. Some conditions may help, but overall the forecast does not strongly support visibility.
Score breakdown
How tonight's aurora score for Trondheim breaks down into activity and visibility components.
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Geomagnetic activity
7 / 40Geomagnetic activity (Kp 3.0) contribution to the score.
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Aurora oval probability
7 / 20OVATION aurora oval probability (9%) contribution.
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Cloud cover
18 / 20Cloud cover (9%) contribution — clear skies score full points.
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Darkness
15 / 15Sky darkness contribution — astronomical darkness scores full points.
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Moonlight
1 / 5Moon illumination (88%) contribution — new moon scores full points.
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Geomagnetic activity (Kp index)
Near thresholdKp measures how disturbed Earth's magnetic field is on a 0–9 scale. Higher Kp pushes the aurora oval toward the equator. Trondheim needs Kp ≥ 4.
Kp is below the minimum needed at this latitude.
Kp is close to the minimum needed — a faint aurora may appear low on the horizon.
Kp meets the threshold for visible aurora here.
Kp is comfortably above the local threshold.
Storm-level Kp ≥ 5 — aurora can be seen far south of its usual zone.
Near threshold
Geomagnetic activity is only marginal for Trondheim: expected Kp is 3.0, while this location usually needs around 4.
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Cloud cover
Clear skiesAverage cloud cover during the best viewing window. Clear skies are essential — even thin overcast hides the aurora.
Up to 25% cloud — excellent visibility.
25–50% cloud — aurora may peek through gaps.
50–85% cloud — most of the sky is blocked.
Over 85% cloud — aurora effectively hidden.
Clear skies
Skies are mostly clear, which is favorable for seeing the aurora.
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Sky darkness
Astronomical darknessAurora is faint and needs a dark sky. Astronomical darkness (sun more than 18° below horizon) is ideal.
Sun stays above 6° below horizon all night — no aurora-friendly darkness.
Sun 6–12° below horizon — too bright for faint aurora.
Sun 12–18° below horizon — sky is dark but not fully astronomical.
Sun more than 18° below the horizon — fully dark sky.
Astronomical darkness
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Moon illumination
Bright moonA bright moon washes out faint aurora colours. New moon is ideal; full moon hides everything but the strongest displays.
Less than 25% illuminated — minimal interference.
25–75% illuminated — faint aurora may be washed out.
Over 75% illuminated — only strong displays will be visible.
Bright moon
Moon is 88% illuminated — expect washed-out faint aurora.
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Aurora oval probability (OVATION)
ModerateNOAA's OVATION model estimates the chance of aurora visible overhead within a 250 km radius of you.
Less than 5% probability — aurora unlikely to reach this location.
5–20% probability — aurora possible.
20–40% probability — aurora likely if skies are clear.
Over 40% probability — aurora very likely overhead.
Moderate
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Aurora zone
Fair zoneHow favourable Trondheim's latitude is for aurora viewing in general — independent of tonight's conditions.
Lower latitude — aurora is rare and requires a major storm.
Mid-latitude — aurora visible only during moderate-to-strong storms.
High-latitude region — aurora is visible on most active nights.
Directly under the auroral oval — aurora is a regular occurrence.
Fair zone
Trondheim is in an occasional aurora region, so stronger geomagnetic activity is usually needed.
Data sources
- · NOAA SWPC Kp forecast
- · NOAA OVATION aurora model
- · Open-Meteo cloud forecast
Aurora Forecast AI Tracker
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Best Months to See the Northern Lights in Trondheim
The aurora season in Trondheim usually runs from September to April.
Drive away from city lights and look toward the northern horizon. Aurora visibility usually requires stronger geomagnetic activity around Kp 4 or higher.