Space Weather
Solar wind speed — live and explained
The speed of the stream of charged particles constantly flowing from the Sun — one of the key inputs that determines whether tonight's aurora activity picks up.
Live Solar Wind Speed
Updated every 10 minutes from live NOAA data.
Source: NOAA DSCOVR/ACE
What is solar wind?
Solar wind is a continuous outflow of charged particles — mostly protons and electrons — streaming from the Sun's outer atmosphere, the corona, at speeds typically between 300 and 800 kilometers per second. It carries the Sun's magnetic field outward through the solar system, and when it reaches Earth, it interacts with our planet's own magnetic field. Faster solar wind, especially when paired with a southward-pointing IMF Bz, compresses and disturbs Earth's magnetosphere — which is what drives geomagnetic storms and aurora.
Typical speed ranges
| Speed | Level | What it means |
|---|---|---|
| < 300 km/s | Slow | Quiet solar wind conditions, minimal geomagnetic effect. |
| 300–400 km/s | Typical baseline | Normal background solar wind speed. |
| 400–500 km/s | Elevated | Often from a coronal hole stream; can contribute to minor activity. |
| 500–700 km/s | Fast | Frequently associated with aurora activity when combined with southward Bz. |
| 700+ km/s | Very fast | Often linked to a fast CME arrival or strong coronal hole stream — elevated storm potential. |
Recent history
The last 24 hours of observed solar wind speed.
FAQ
Why does solar wind speed matter for aurora?
Faster solar wind delivers more energy into Earth's magnetosphere, especially when combined with a southward IMF Bz. Speed alone doesn't guarantee aurora — direction of the magnetic field matters just as much — but sustained high speeds (500+ km/s) raise the odds of geomagnetic activity.
What causes fast solar wind?
Two main sources: coronal holes — open regions in the Sun's magnetic field that let solar wind escape more freely — and coronal mass ejections, which can briefly push speeds well above 1,000 km/s.