Planetary Kp Index Map for the U.S. and Canada. Click for a larger version.
The planetary Kp index tonight (October 7 into the early hours of October 8) is projected to be 7. That is one of the highest readings in months. If you live north of the yellow line on the map above, your odds of seeing the Northern Lights are good. Of course you need clear, dark skies. That means little or no clouds, no moon, and you need to be far away from big city lights.
You can check out the projected Kp index (also called the K-index) at the Space Weather Prediction Center (SWPC) and sign up for notifications by email if you don’t want to be checking the web site all the time. Once you know the Kp index you can check the map. The colored lines show the southern limit of visibility for a given Kp index.
Keep in mind the Kp index is an estimate. Sometimes, despite a good Kp index, you stay up late and the Northern Lights don’t happen. So you sip your thermos of hot chocolate and enjoy the stars. Like most kinds of nature photography there are no guarantees.
SWPC Screen Capture. October 7, 2015.
Look for the “The Aurora” and click to see a much larger video. Click on the “Estimated Planetary K-Index” to see a larger version. This is a screen capture from the SWPC site so the video and link do not work. All times are UTC so subtract several hours to convert UTC to your local time. For example, EDT in the U.S. is four hours behind UTC, so 3:00 am October 8 UTC is 11 pm October 7 EDT. PDT in the U.S. is seven hours behind UTC.
Screen Capture from an SWPC Aurora Video in the early hours of October 7, 2015.
Estimated Planetary K Index Chart
To photograph the Northern Lights, read How To Photograph the Northern Lights.
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