Aurora Borealis Forecast

Kp index — live and 3-day forecast

1.3

As of

059G1 stormNowOct 1Oct 2Oct 3Oct 4Oct 5Oct 6Oct 7Oct 8Oct 9Oct 10Oct 11
Kp forecast values
Kp forecast by 3-hour bin
TimeKpKind
0.3observed
0.3observed
0.7observed
1.0observed
1.0observed
1.3observed
1.3observed
2.0observed
1.0observed
1.0observed
0.3observed
0.7observed
0.7observed
0.3observed
0.7observed
1.3observed
2.3observed
2.7observed
2.7observed
2.0observed
1.7observed
0.7observed
0.3observed
1.0observed
3.0observed
3.3observed
4.3observed
5.0observed
4.7observed
4.3observed
5.7observed
4.7observed
4.0observed
5.3observed
2.3observed
3.3observed
2.7observed
3.7observed
3.7observed
4.0observed
3.0observed
3.0observed
2.3observed
2.7observed
2.7observed
1.7observed
2.0observed
2.3observed
1.0observed
1.3observed
1.0observed
0.7observed
1.0observed
2.7observed
2.3observed
1.0observed
1.0observed
1.7observed
1.0observed
2.0observed
2.0observed
1.3observed
1.7estimated
1.7estimated
1.7predicted
5.0predicted
5.7predicted
5.0predicted
4.7predicted
4.0predicted
4.0predicted
3.3predicted
4.0predicted
3.7predicted
3.0predicted
3.0predicted
2.7predicted
2.3predicted
2.3predicted
2.7predicted
4.0predicted

Space weather data from NOAA, updated . Refreshed every 5 minutes.

What Kp do I need to see the northern lights?

From the NOAA Space Weather Scales (geomagnetic storms):

KpStorm levelWhere aurora can be seen (NOAA)
5G1 MinorCommonly visible at high latitudes (northern Michigan and Maine)
6G2 ModerateSeen as low as New York and Idaho (~55° geomagnetic latitude)
7G3 StrongSeen as low as Illinois and Oregon (~50°)
8G4 SevereSeen as low as Alabama and northern California (~45°)
9G5 ExtremeSeen as low as Florida and southern Texas (~40°)

Kp needed by city

CityKp needed
Fairbanks, AK3.9
Anchorage, AK4.6
Seattle, WA6.4
Spokane, WA6.3
Portland, OR6.8
Missoula, MT6.3
Boise, ID7.0
Bismarck, ND6.1
Fargo, ND6.0
Duluth, MN5.9
Minneapolis, MN6.3
Marquette, MI5.9
Milwaukee, WI6.6
Chicago, IL6.9
Detroit, MI6.7
Buffalo, NY6.6
Burlington, VT6.3
Portland, ME6.4
Boston, MA6.7
Denver, CO7.5

Kp needed comes from the NOAA Space Weather Scales, which give latitudes for Kp 6–9. Values for places north of about 55° geomagnetic latitude (including Alaska) are our extrapolation. NOAA notes that even at Kp 0 the edge of the auroral oval sits near 66° geomagnetic latitude, so interior Alaska can see aurora on quiet nights. How we calculate this.

FAQ

What is the Kp index?

Kp measures how disturbed Earth's magnetic field is, on a scale from 0 (calm) to 9. NOAA describes it as the average of standardized K-index readings from 13 geomagnetic observatories between 44° and 60° geomagnetic latitude. Each value covers a 3-hour period, and Kp 5 or higher counts as a geomagnetic storm. Source: NOAA SWPC, Planetary K-index.

Is a higher Kp better for seeing the northern lights?

Yes. As Kp rises, the auroral oval expands toward the equator, so the aurora can be seen farther south. NOAA puts the oval's southern edge near 66° geomagnetic latitude at Kp 0, and says that around Kp 6–7 the aurora may be visible from the northern edge of the United States. The aurora can also be seen hundreds of miles south of where it is overhead, low on the northern horizon.

How accurate is the Kp forecast?

NOAA's 3-day Kp forecast is most reliable for the next few hours. Storm timing a day or more out can be off by several hours, and some forecast storms fizzle. Check again at dusk. NOAA's 30-to-90-minute aurora forecast (the OVATION map on our forecast page) is the best short-range guide.

What time is best to see the northern lights?

NOAA says the best aurora is usually within an hour or two of midnight, between about 10 PM and 2 AM local time. NOAA also names the weeks around the spring and fall equinoxes as the best seasons. In summer, far-northern places like Alaska don't get dark enough.

What else matters besides Kp?

You need darkness, clear skies, and a view to the north. Get away from city lights. A full moon dims how bright the aurora looks. Our tonight tool checks darkness, cloud cover and the moon for your ZIP code.

Viewing tips source: NOAA SWPC, Tips on Viewing the Aurora.