- What is the KP index and how often is it updated?
- The planetary K-index (Kp) measures global geomagnetic activity on a scale of 0-9, updated every 3 hours by NOAA's Space Weather Prediction Center (SWPC) using data from 13 magnetometer observatories worldwide. This tool fetches the latest Kp data directly from the NOAA SWPC public JSON API and displays it in real time.
- What KP index is needed to see the northern lights?
- At Kp 3-4, aurora is visible at high latitudes (above ~64°). Kp 5 (G1 storm) brings aurora to ~58° latitude — visible from Scotland, southern Scandinavia, and central Canada. Kp 7 (G3) reaches ~48°, making aurora visible from the northern continental US and central Europe. You also need dark, clear skies — use our Twilight Calculator to find when astronomical darkness begins.
- Where does the KP data come from?
- Data is fetched directly from NOAA SWPC's public API (services.swpc.noaa.gov). The planetary K-index is derived from 3-hour magnetometer readings at 13 stations: Fredericksburg (USA), Sitka (USA), Meanook (Canada), Ottawa (Canada), Lerwick (UK), Lovedean (UK), Hartland (UK), Eskdalemuir (UK), Niemegk (Germany), Wingst (Germany), Brorfelde (Denmark), Uppsala (Sweden), and Canberra (Australia).
- Can I see the aurora tonight in my location?
- Check the current Kp value above. If Kp is 5 or higher and you are at latitudes above ~55°, you have a good chance. For the best viewing: (1) get away from city lights, (2) find a north-facing horizon, (3) check that it's astronomically dark using our Twilight Calculator, and (4) verify the Moon phase isn't washing out the sky with our MoonSync tool. — KP Index Aurora Forecast, fastool.io