Forecast Lead Time
Estimate how long current solar wind conditions may take to reach Earth.
About Forecast Lead Time
Calculation Method
Lead time is estimated with: Distance ÷ Solar Wind Speed
- The average distance from the L1 point to Earth is about 1.5 million kilometres.
- Solar wind speed is measured in kilometres per second (km/s).
- The result is converted into minutes for easier interpretation.
How to Interpret It
- Faster solar wind means shorter warning time.
- Slower solar wind means longer warning time.
- This is not the exact aurora arrival time, only the estimated lag from L1 data to Earth.
Why It Matters
Lead time helps aurora watchers judge how quickly changes in solar wind speed, density or magnetic field might begin to affect Earth.
L1 Satellite Data
The Solar Wind Speed, Proton Density and Magnetic Field cards all use measurements from satellites near the L1 Lagrange point, so the lead time applies directly to those values.
This page is automatically generated from the public data sources listed below. The information is not quality controlled and may not update in a timely manner, so you accept all risks and responsibility arising directly or indirectly from using it, including data from NOAA SWPC, BOM SWS, Canadian Space Agency, SGO, IRF, Natural Resources Canada and City of Hobart.