Real-time space weather from NOAA — Kp index, geomagnetic storm alerts, solar flares, and how today's solar activity affects the ISS, Starlink satellites, and aurora visibility tonight.
The Kp index is a 0-9 scale measuring global geomagnetic activity, updated every 3 hours by NOAA. Kp 0-1 is completely quiet. Kp 5 is a minor geomagnetic storm (G1). Kp 9 is extreme (G5) — the level that caused the May 2024 aurora visible from southern Australia and the US. Most days sit around Kp 1-3.
During geomagnetic storms, Earth's upper atmosphere heats and expands. Satellites in low Earth orbit — including the ISS at 420km and Starlink at 550km — experience increased atmospheric drag, causing their orbits to decay faster than normal. During the May 2024 G5 storm, SpaceX put hundreds of Starlinks into safe mode and several dropped altitude noticeably. The ISS requires regular altitude boosts anyway, but storms increase the frequency needed.
Aurora visibility depends on Kp index and your latitude. At Kp 5 (G1 storm) aurora reaches to about 60° geomagnetic latitude — roughly Scotland, southern Canada, or northern Scandinavia. At Kp 7 it reaches ~55°, at Kp 9 potentially as low as 40° — central Europe and the northern US. Check the live Kp reading above. If it's 5 or higher, go outside and look north (or south if you're in the southern hemisphere).
Yes, but modestly. During active periods, increased drag causes small timing errors in pass predictions — typically a few seconds for the ISS over a 24-hour window. For precise timing during a storm, use a fresh prediction from within 6 hours of the pass. OrbitalNodes refreshes TLE data multiple times daily to minimise this effect.
The May 2024 event was a G5 extreme geomagnetic storm — the strongest since the Halloween storms of 2003. Kp reached 9 and aurora was visible from Spain, Italy, Mexico, and southern Australia. SpaceX reported Starlink satellites were stressed by the increased atmospheric drag. The storm was caused by a series of X-class solar flares and coronal mass ejections from a highly active sunspot region.