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Goddard Space Flight Center

Space Weather Action Center

Space Weather Action Center


KP Index (Estimated Planetary K-index) Tutorial:

Getting to the Data:

Open and click on "Kp Index" (live data). A web page containing a bar graph called the "Estimated Planetary K-index (3-hour data)" will appear. Observe the graph for any deviations. (K-indices of 5 or higher indicate 'storm-level' geomagnetic activity. Values of 7 or higher indicate a severe geomagnetic storm.)

About the Data:

Every three hours throughout the day, magnetic observatories around the world measure the largest magnetic change that their instruments recorded during this time. The result is averaged together with those of the other observatories to produce an index that tells scientists how disturbed the Earth's magnetic field is on a 9-point scale. This scale is called the Kp scale. The larger the index (7+) the more active the Earth's magnetic field becomes due to a storm from the sun. The smaller the index (1-2) the more quiet it is. Sometimes changes in the suns activity can cause big changes in Kp. At other times, large Kp values can indicate sudden rearrangements of the Earth's magnetic field due to the solar wind. Kp-indices of 5 or greater indicate storm-level geomagnetic activity.

KP Index graph


Analysis Tip:

The vertical axis shows the Kp index from 0 to 9. The horizontal axis shows 3 hour estimated data recorded in Universal Time (UT).

  • GREEN BARS show a Kp index less than 4 (indicates little magnetic change)
  • YELLOW BARS show a Kp index equal to 4 (indicates moderate magnetic change)
  • RED BARS when the Kp is greater than 4 (indicates a storm warning)

* Kp values greater than 7 indicate a large disturbance.

The estimated Kp index is derived at the U.S. Air Force Space Forecast Center using data from ground-based magnetometers: Meanook, Canada; Sitka, Alaska; Glenlea, Canada; Saint Johns, Canada; Ottawa, Canada; Newport, Washington; Fredericksburg, Virginia; Boulder, Colorado; and Fresno, California. These data are made available through the cooperation of the Geological Survey of Canada (GSC) and the US Geological Survey.

Converting to Universal Time (UT)

Note: UT is the same as Greenwich Mean Time.

Eastern Standard + 5 hours = UT
Central + 6 hours = UT
Mountain + 7 hours = UT
Pacific + 8 = UT
Alaska Standard Time + 9 = UT

Note: For Daylight Savings Times

Eastern Daylight Savings + 4 hours = UT
Alaska Daylight Savings + 8 hours = UT

KP Auroral Map

KP Index graph


The KP Auroral Map tool shows the connection between Kp Index and the predicted southern edge of the aurora in North America.

  • Kp of 3: aurora could be expected south to the BLUE line.
  • Kp of 5: aurora could be expected south to the GREEN line.
  • Kp of 9: aurora could be expected south to the RED line.
  • Kp of 9+: aurora could be seen as far south as Texas and Florida.

Click anywhere on the map to see the Geographic Longitude, Geographic Latitude, and Corrected Magnetic Latitude for that location.

[This tool was developed by NOAA, in Boulder Colorado, and may be used to determine locations of possible auroral sightings.]

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