Geomagnetic Storms Today: Kp Index and Forecast
Current Kp index, the 3-day forecast in 3-hour steps and the 27-day storm calendar — from NOAA data, updated hourly.
Kp index by 3-hour intervals
Dashed cells are NOAA forecast; the rest are observed or estimated values. Times are UTC.
A geomagnetic storm is a disturbance of the Earth's magnetic field caused by a burst of solar wind or a coronal mass ejection reaching the planet. Its strength is measured by the planetary Kp index on a scale from 0 to 9, calculated every three hours from magnetometer stations around the world. Kp 0–3 means quiet conditions, 4 is unsettled, and from Kp 5 it is a storm, graded G1 to G5 on the NOAA scale. This page shows the current Kp, the values for each three-hour interval of yesterday and today, and NOAA's forecast for the next three days.
Below is the 27-day outlook: the largest Kp expected each day. It relies on the Sun's 27-day rotation — active regions that caused a storm tend to face the Earth again a month later — so treat it as a rough guide, not a precise forecast. All data come from the NOAA Space Weather Prediction Center and the page is refreshed every hour. Storms matter for satellites, GPS, radio and power grids, and strong ones bring the aurora far south.
27-day outlook: largest expected Kp per day (NOAA)
Next storm-level day in the 27-day outlook: Wed 21 October (Kp 5).
| Date | Max Kp | Level |
|---|---|---|
| Sun 11 October | 3 | Quiet |
| Mon 12 October | 3 | Quiet |
| Tue 13 October | 3 | Quiet |
| Wed 14 October | 3 | Quiet |
| Thu 15 October | 2 | Quiet |
| Fri 16 October | 2 | Quiet |
| Sat 17 October | 2 | Quiet |
| Sun 18 October | 2 | Quiet |
| Mon 19 October | 2 | Quiet |
| Tue 20 October | 2 | Quiet |
| Wed 21 October | 5 | G1 minor storm |
| Thu 22 October | 5 | G1 minor storm |
| Fri 23 October | 4 | Unsettled |
| Sat 24 October | 3 | Quiet |
| Sun 25 October | 2 | Quiet |
| Mon 26 October | 2 | Quiet |
| Tue 27 October | 2 | Quiet |
| Wed 28 October | 2 | Quiet |
| Thu 29 October | 2 | Quiet |
| Fri 30 October | 2 | Quiet |
| Sat 31 October | 5 | G1 minor storm |
| Level | Kp | What it means |
|---|---|---|
| G1 minor | 5 | Weak power grid fluctuations; aurora at high latitudes (northern Norway, Finland) |
| G2 moderate | 6 | Voltage alarms in high-latitude grids; aurora may be seen down to about 55° geomagnetic latitude |
| G3 strong | 7 | Intermittent GPS and HF radio problems; aurora down to about 50° — often visible in the Baltic states |
| G4 severe | 8 | Widespread voltage control problems, GPS degraded for hours; aurora down to about 45° |
| G5 extreme | 9 | Possible grid failures and radio blackouts; aurora seen far south, as in May 2024 |
Discover your destiny!Tarot MagicTarot card readingsStart Reading ✦Frequently Asked Questions
What is the Kp index?
Kp is a planetary index of geomagnetic activity from 0 to 9, computed every three hours from a network of ground magnetometers. Values like 4.67 or 5.33 are the thirds of the scale (5−, 5+). Kp 5 and above counts as a geomagnetic storm.
What do the G1–G5 levels mean?
They are NOAA's storm scale: G1 (minor) at Kp 5, G2 (moderate) at Kp 6, G3 (strong) at 7, G4 (severe) at 8 and G5 (extreme) at 9. Over a solar cycle G1 storms occur on roughly 900 days, while G5 storms happen only a few times.
How accurate is the forecast?
The 3-day forecast is reasonably reliable for quiet days and for storms from coronal mass ejections already seen leaving the Sun, though their arrival time can be off by many hours. The 27-day outlook only assumes that active regions return with the Sun's rotation, so it is a rough guide.
Do magnetic storms affect health?
The evidence is limited and mixed. Some studies find weak statistical links between geomagnetic activity and blood pressure or heart rate, others find none, and no mechanism is established. If you feel unwell, the cause is far more likely something else — see a doctor rather than rely on the Kp index.
Can I see the aurora during a storm?
The stronger the storm, the further south the aurora reaches. In the Baltic states it is often visible at G3 and above, in central Europe and Ukraine usually only at G4–G5. You also need a clear, dark sky away from city lights, looking north.
Why are the times shown in UTC?
NOAA publishes Kp in Universal Time. The English version keeps UTC; the Ukrainian and Russian versions convert to Kyiv time, the Lithuanian one to Vilnius time and the French one to Paris time.
What do the dashed cells mean?
They are forecast values. Solid cells are observed Kp or NOAA's estimate for the most recent hours, which can be revised slightly once all stations report.
What do storms affect in practice?
Satellite navigation (GPS accuracy drops), shortwave radio, satellites in orbit and long power lines at high latitudes. For most people the only visible effect is the aurora.
How often is the page updated?
The page is rebuilt every hour with the latest NOAA data; Kp itself is published every three hours. The 27-day outlook is issued once a week.
Where does the data come from?
From the NOAA Space Weather Prediction Center (USA): the planetary K-index forecast and the 27-day space weather outlook. The data are public and free.