About the northern lights

Green: good opportunities. Yellow: opportunities. Red: limited by weather or light. Grey: insufficient or outdated data. The assessment applies to the place and time you are viewing, including a preview. Colours are guidance, never a guarantee.

Yes. Tromsø lies in the auroral belt, where low Kp can still bring rewarding displays. Kp describes global geomagnetic activity, not the exact local aurora activity. Aurora’s guidance rule is “Opportunities” below Kp 2 and “Good opportunities” from Kp 2, subject to clouds and darkness. This is a product rule, not a scientific probability threshold.

Clouds and a bright sky can hide active aurora. High Kp alone therefore does not produce a green assessment. Partial cloud cover can leave gaps, but the forecast cannot pinpoint exactly where those gaps will appear.

“Estimated” means weather data is calculated from suitable nearby references. Local conditions may differ. “Unknown” means there is no valid basis for that place and time; it does not necessarily mean poor conditions.

Aurora attempts to refresh weather data every 30 minutes. Your browser checks published forecasts every 5 minutes while the tab is active, and checks again when you return. The source may still have the same forecast, so a check does not always mean new weather data. Errors may delay retrieval. Technical access renewal can happen more often but does not fetch new weather data. Your chosen place and time are retained.

The slider and “Play” preview other times. Map assessments follow the preview. “Use time” confirms it as your evening time. Playback never changes your chosen evening place or time automatically.

The landscape image is an illustrative photograph. The animation illustrates forecast data for the displayed time. It is neither a live camera nor a confirmed observation.

No. Green means the forecast basis is favourable. Aurora and local weather can change. Use the assessment to compare places and times.

Phone: use night mode, a steady support or tripod, and switch off the flash. Avoid digital zoom. Try 3–10 seconds if supported; use a shorter exposure for fast movement. Lower exposure if highlights burn out.

Camera: use a tripod, a wide-angle lens and focus on the stars. Start at f/1.8–2.8, ISO 1600 and 2–5 seconds. Adjust for brightness and movement; RAW is optional. Choose a simple foreground and avoid bright lights facing the lens. These are starting points, not fixed settings. A camera can show stronger colours than your eyes.

Dress more warmly for standing still than for walking. Wear wool next to your skin, wool or fleece mid-layers, an extra warm jacket and a windproof outer layer. Choose waterproof outerwear in precipitation. Bring a hat, neck warmer, mittens and warm, roomy winter boots with wool socks. A sitting mat, a warm drink and ice grips can help. Check temperature and wind, and have somewhere to warm up.