Aurora Forecasts vs. Real Aurora Data: What We Use

Most aurora apps predict the future. We document the past — the exact Kp index and solar wind speed on your special night.

Kp Index and Solar Activity

The Kp index is a scale from 0 to 9 used to measure geomagnetic activity. We fetch historical indexes from NOAA's Space Weather Prediction Center (SWPC) to map the exact cosmic storm on your special date.