# Northern lights forecast with the live Kp index from NOAA > Live Kp index, NOAA's 3-day and 27-day Kp outlook and the aurora probability over 30 northern lights destinations from Iceland to Tasmania. Canonical: https://kpforecast.com/ Updated on: 2026-10-08 The planetary Kp index measured by NOAA SWPC right now, its forecast in 3-hour slots for the next three days, the 27-day outlook and the aurora probability over 30 destinations in both hemispheres. ## In short The northern lights forecast on kpforecast.com is the planetary Kp index from NOAA SWPC: the value measured in the last 3-hour interval, the forecast for the next three days in 3-hour slots and the 27-day outlook with the largest Kp expected per day. The aurora probability over Reykjavik, Tromsø, Rovaniemi, Fairbanks, Yellowknife, Hobart and 24 more places comes from NOAA's OVATION model. Everything refreshes every 15 minutes. ## Kp index right now ## Aurora probability now over 30 northern lights destinations ## Kp forecast for the next 3 days [[KP_3DAY]] ## 27-day outlook: largest Kp expected per day [[KP_27DAY]] ## How to read the Kp index The Kp index describes geomagnetic activity on a scale from 0 to 9. NOAA's viewing tips put the equatorward edge of the auroral oval at about 66 degrees geomagnetic latitude for Kp 0, moving roughly 2 degrees toward the equator with each Kp step, down to about 48 degrees at Kp 9. The relationship is approximate and refers to geomagnetic latitude, not the latitude on a map. NOAA's G scale starts at Kp 5: G1 is Kp 5, G2 is Kp 6, G3 is Kp 7, G4 is Kp 8 and G5 is Kp 9. Right under the oval, in places such as Tromsø or Fairbanks, NOAA notes that good displays are possible even at Kp 3 or 4. A high Kp is not enough on its own. The sky has to be dark and clear, away from city lights, and a full moon makes the aurora look fainter. At the latitudes where the aurora is most common it does not get dark in summer. ## Where the data comes from and how far it reaches Every number on this page comes from NOAA SWPC, the Space Weather Prediction Center of the US National Oceanic and Atmospheric Administration. The observed Kp arrives in 3-hour intervals, the forecast covers 3 days in 3-hour slots and the 27-day outlook gives the largest Kp expected per day. Beyond those 27 days there is no forecast, and this page does not invent one. The aurora probability per destination comes from NOAA's OVATION model, a 30 to 90 minute forecast of where the aurora is and how intense it is. How each value is read is explained under [Data and method](https://kpforecast.com/about/). ## Frequently asked questions ### What Kp index do you need to see the northern lights? It depends on how far north you are, in geomagnetic latitude. According to NOAA's viewing tips the auroral oval reaches about 66 degrees geomagnetic latitude at Kp 0 and moves roughly 2 degrees closer to the equator with each Kp step. Under the oval, in northern Norway, Lapland, Iceland or Alaska, NOAA notes that Kp 3 or 4 can already bring a good display. ### How far ahead can the northern lights be forecast? NOAA SWPC publishes a detailed Kp forecast for 3 days in 3-hour slots and a 27-day outlook with the largest Kp expected per day. The 27-day outlook is a daily maximum, not a forecast for a particular night. Beyond 27 days there is no forecast at all, so no page here shows one. ### Is the 27-day Kp index outlook a northern lights forecast for a specific night? No. It lists the largest Kp on the 0 to 9 scale that NOAA expects on each day, which is useful to tell quiet and active periods apart. Whether the aurora is visible on a given night also depends on darkness, clouds and the moon, none of which the outlook includes. ### How often are the Kp index and the northern lights data on kpforecast.com updated? The site fetches the NOAA SWPC products and keeps them for at most 15 minutes before asking again, and each live block shows the time of its last fetch. The observed Kp itself is a value for a 3-hour interval, so it changes at most every three hours. When NOAA does not respond, the page says so instead of showing an old or invented value. ### Does the aurora probability per northern lights destination come from the Kp index? No. It comes from the OVATION model published by NOAA SWPC, a 30 to 90 minute forecast of the location and intensity of the aurora on a grid of one degree. For each destination the page reads the grid point closest to its coordinates. The value is a probability in percent, not a guarantee. ### Can you see the northern lights in summer in Tromsø or Iceland, even with a high Kp index? Rarely. Tromsø sits at 69.6 degrees north, and NOAA's viewing tips point out that the high latitudes where the aurora occurs do not get dark in summer. Without a dark sky even strong activity stays invisible. The Kp index on this site keeps updating all year, but at high latitudes the viewing season is the dark part of the year. ### Does a high Kp index guarantee northern lights? No. Kp describes geomagnetic activity, not the sky above you, and NOAA's G scale only starts at Kp 5. You also need darkness, a clear sky and a place away from city lights, and NOAA notes that a full moon makes the aurora look fainter. A high Kp mainly means the aurora can be seen further from the poles than usual. ## Sources - [NOAA SWPC, Planetary K-index](https://www.swpc.noaa.gov/products/planetary-k-index), checked on 2026-10-08 - [NOAA SWPC, 3-Day Forecast](https://www.swpc.noaa.gov/products/3-day-forecast), checked on 2026-10-08 - [NOAA SWPC, 27-day Space Weather Outlook Table](https://services.swpc.noaa.gov/text/27-day-outlook.txt), checked on 2026-10-08 - [NOAA SWPC, Aurora 30 Minute Forecast (OVATION)](https://www.swpc.noaa.gov/products/aurora-30-minute-forecast), checked on 2026-10-08 - [NOAA SWPC, Tips on viewing the aurora](https://www.swpc.noaa.gov/content/tips-viewing-aurora), checked on 2026-10-08 - [NOAA Space Weather Scales](https://www.swpc.noaa.gov/noaa-scales-explanation), checked on 2026-10-08