Aurora History Explained: Heatmap, Best Months, and Last Seen
How Aurora History works in Aurora Forecast app: multi-year Kp data, calendar heatmaps, best-month selection, and local last-seen observation windows.
Aurora History in Aurora Forecast is built for planning, not hype. It summarizes long-term aurora patterns for a location and helps you answer: "When should I come here to maximize my chance?"
What Aurora History Shows
- Total aurora nights estimate for the selected location.
- Best months based on historical activity patterns.
- Calendar heatmap that breaks activity into month/week blocks.
- Recent local windows such as last-seen and yesterday observations.
Data Foundation (Why It Is Useful)
The feature uses a multi-year geomagnetic archive (GFZ + NOAA sources) instead of a single-season snapshot. This helps reduce random bias from unusually active or unusually quiet short periods.
- Historical Kp measurements across many years
- Location-specific magnetic-latitude thresholding
- Darkness filtering to avoid counting non-visible daylight intervals
Best Months: Not Just One Number
Aurora History does not pick a random "best month." It uses tiered selection so you can see both top months and close alternatives when activity is statistically similar.
| Output Element | Why It Matters |
|---|---|
| Primary best month | Gives the strongest default recommendation. |
| Secondary months (when close) | Helps with flexible travel dates and pricing constraints. |
| Weekly heatmap distribution | Prevents overconfidence from a monthly average alone. |
How to Use It in Real Planning
- Open Aurora History for your destination.
- Start with best months, then compare weekly heatmap cells.
- Choose a 3-5 night window instead of a single fixed date.
- Before the trip, switch to 72h forecast + live status.
History helps you choose the season. Live forecast helps you choose the exact night.
Common Misunderstanding
History is a probability baseline, not a guarantee
A strong historical month does not guarantee clear skies on your exact dates. Use history for timing strategy, then confirm clouds, darkness, and current geomagnetic activity in the app before going out.
Combine with These Features
- Aurora Alerts to avoid missing short visibility windows.
- Nearest Active Aurora when your exact location is blocked by clouds.
- World Map Layers for cloud/daylight context.
Sources
- NOAA SWPC — Planetary K-index — historical and real-time geomagnetic data
- GFZ Potsdam — Geomagnetic Kp Index — historical Kp archive since 1932
- NOAA SWPC — Solar Cycle Progression — 11-year solar cycle history
