Kp index and the aurora: explained from Kp0 to Kp9
What does the Kp4 index mean? And what about Kp5? Can you see the northern lights at Kp2 or even Kp0? And what exactly should you expect from each Kp level?
Kp0 and soft glow of the northern lights above the horizon.
The general rule is that as the Kp index rises, the aurora extends further from the polar regions toward the equator and becomes more active, bright, and colorful. Let's see what each Kp level means for the aurora.
Important note. To experience all the beauty of the aurora, you have to be in a location where you can see auroras overhead. If your location allows you to have auroras only on the horizon, you will usually see only the upper red part of the lights. Read what Kp index you need for auroras overhead or on the horizon.
Kp0
The Kp0 index means faint inactive aurora that is unlikely visible to the naked eye. Nevertheless, you can capture its soft glow on a digital camera in one of the northernmost locations like Yellowknife and Churchill in Canada or Tromso in Norway.
Kp1
At the Kp1 level, the aurora is also faint and inactive and usually looks grey because the human eye can't detect the colors of very dim objects. Still, it's classic green in the images. The northern lights extend a bit south. You can capture the green glow in the sky in the most popular aurora regions like Lapland, Iceland, or northern Canada.
Kp2
At Kp2, the aurora becomes slightly active, and you won't confuse it with a grey cloud. The glowing bow starts transforming into something else but with no significant success. Sometimes you can notice a faint red glow in the upper part of the northern lights. Though the Kp2 indicates low aurora activity, you can see it in all popular northern lights regions at that level.
Kp3
It's a good level if you are in the northern region. The aurora becomes more active and colorful. Sometimes you can see the bright pink low edge of it. At Kp3, the aurora extends a bit south, and you can already capture it in Jasper National Park or the Faroe Islands, but only on the northern horizon.
Kp4 and the fantastic northern lights all over the sky.
Kp4
The Kp4 is already an excellent level for the northern lights. You can witness them all over the sky if you are in the right place. Northern lights are moving fast as curtains in the wind. The dominant color is green, but you will see some purple, red, or pink tints. At Kp4, you can photograph the northern lights, at least on the horizon, in most of Finland, Norway, Sweden, Banff National Park, or even Minnesota.
Kp5
At Kp5, the northern lights are bright and active, with even more purple, pink, and red colors. This level is considered a first-category geomagnetic storm (G1). It's already enough to see the southern lights in the southern parts of Tasmania and New Zealand, but only on the southern horizon. In the northern hemisphere, you can already see the aurora in almost all of Canada, at least on the horizon, in Scotland or Estonia.
Kp6
The Kp6 is a G2 geomagnetic storm. The Northern and southern lights extend further toward the equator. You can see them in Denmark, Latvia, Vancouver Island, or Montana national parks. And, of course, they are more active, bright, and colorful than at Kp5.
Kp7
The Kp7 or G3 geomagnetic storm is a very high activity level, which means absolutely fantastic aurora. Suppose you are lucky and the sky is clear. In that case, you can take amazing pictures of all those green, purple, pink, and red rays or arrows piercing the sky above your head in Yellowstone National Park, Ireland, Scotland, the south coast of Australia, or the South Island of New Zealand. On the horizon, you can see the aurora even in the Wellington region, New Zealand.
Kp8
The Kp8 or G4 geomagnetic storm is a unique event. The northern and southern lights extend so far towards the equator that they can be seen in highly unusual regions for aurora photography, such as New Zealand North Island, Netherlands, or the north coast of Germany.
Kp9
The Kp9 or G5 is the highest level on the scale from Kp0 to Kp9 and is an absolutely unique aurora event. Imagine the colorful aurora dancing in the sky in New York, London, Amsterdam, or Colorado national parks. Unbelievable, but it's possible in the coming years with the increasing solar activity.
