Is there a geomagnetic storm right now?

4.33

No storm

updated 2 h ago

Planetary K-index (Kp), latest 3-hour value

NOAA's latest estimate of the Kp index, for the last completed three-hour interval, is 4.33. Kp measures how hard Earth's magnetic field is being shaken. At Kp 5 or above, NOAA counts a geomagnetic storm. Its own data also label a reading a third lower as a minor storm, so a number just under the line can count too. Lower than that, there is no storm. Kp always describes the recent past, not this minute. Upstream of Earth, the wind from the Sun is blowing at 340 kilometres per second.

Planetary K-index (Kp), latest 3-hour value

4.33

Measured, with error

updated 2 h ago

Solar wind speed measured upstream of Earth

340 km/s

Measured

updated 12 min ago

Kp level at which a geomagnetic storm begins (G1)

Measured

Time since the May 2024 storm reached G5

2 y 172 d 15 h

Measured

Time since the Carrington event

167 y 58 d 21 h

Measured

What a storm is

What is a geomagnetic storm?

The Sun never stops breathing out charged gas. This thin, hot wind streams past Earth all the time. Since you opened this page, it has travelled 0 kilometres.

Earth has a shield against it: its magnetic field. The field reaches far out into space, and all of us live inside it. It turns most of the wind aside, though not all of it. Some of the wind's energy always leaks in.

Sometimes the Sun throws a vast cloud of charged gas our way. Or a fast stream of wind catches up with the slower wind ahead of it. When either reaches Earth, the magnetic field we live inside shakes for hours, and in the biggest storms for days. That shaking is a geomagnetic storm. It is strongest when the gas carries magnetism pointing the opposite way to Earth's own, which lets more energy pour in. Most storms are minor. A few light up skies far from the poles.

150,000,000 kmEarth's average distance from the Sun in kilometres

Measured upstream

A wind from the Sun, measured on the way

The wind crosses about 150 million kilometres of space to reach us. If it kept today's speed all the way, it would need about 5.1 days for the trip. An airliner at cruising speed would need about 19 years. At the same speed, the wind would cover the distance from London to New York in about 16 seconds.

We sample it before it arrives. Spacecraft wait at a balance point called L1, about 1.5 million kilometres towards the Sun. The wind they measure reaches Earth about 3,750 seconds later. That is roughly an hour, and less when the wind is fast.

The speed on this page is a one-minute reading from a NOAA spacecraft at L1. It is published a few minutes after it is measured. So it is a little behind the spacecraft, and still ahead of the wind that will reach us.

340 km/sSolar wind speed measured upstream of Earthupdated 12 min ago

Fast enough to cover the distance from London to Sydney in 50 seconds.
Fast enough to cover the distance around Earth in 2 minutes.
Fast enough to cover the distance from Earth to the Moon in 19 minutes.

Every three hours · The G-scale

What Kp measures, and when a storm begins

Magnetometers on the ground feel the field shake. NOAA combines readings from a network of them into one number, the planetary K-index, or Kp. It runs from calm at the bottom to 9 for the most disturbed.

Each value covers three hours of UTC time, and it is only published once those hours have ended. So the Kp here always describes the recent past. It is also an estimate, worked out quickly from fewer stations. The official Kp, from Germany's GFZ research centre, comes later and can differ slightly.

NOAA's storm scale starts with a minor storm, G1, at Kp 5. Each step up adds a level, to extreme, G5, at Kp 9. Kp moves in steps of a third, and the edge is not quite sharp. NOAA's own data already label a reading a third below the line as G1. Strong storms can strain power grids, disturb satellites and blur radio and navigation signals.

4.33Planetary K-index (Kp), latest 3-hour valueupdated 2 h ago

The solar cycle

The breath of the Sun

The Sun's activity rises and falls over about 11 years. At the low point it shows few sunspots. At the high point it is crowded with them, and the giant eruptions that can drive storms come more often. In an average cycle, NOAA counts about 1,700 minor storms. Extreme ones come only about 4 times per cycle, and some cycles have none.

The cycle we are in, Solar Cycle 25, began in December 2019, when the Sun was at its quietest. In October 2024, NASA and NOAA announced that the Sun had reached the maximum period of the cycle. The Royal Observatory of Belgium, which keeps the world's sunspot record, later placed the peak in that same month.

So as of late 2026 we are on the far side of the peak. NOAA expects the next cycle to begin some time between January 2029 and December 2032. Then the Sun's slow breath starts again.

6 y 334 d 14 hTime since Solar Cycle 25 began

Aurora

Lights in our sky

Aurora shine when electrons from space stream down Earth's magnetic field and strike gas high in the air. Oxygen glows green, and higher up, red. Nitrogen can add a purple fringe.

On quiet nights the aurora stays in two rings around the magnetic poles. As storms grow, the rings spread towards the equator. NOAA says aurora have been seen down to about 55 degrees of geomagnetic latitude in a moderate storm. In an extreme one, they have reached about 40 degrees.

Geomagnetic latitude is measured from the magnetic pole, not the geographic one. So the same Kp means different skies in different places. This page cannot tell you what you will see tonight. NOAA's short-range aurora forecast is made for that. What this page can say is what the light means. Each aurora is a storm made visible: energy from the Sun, let in through our shield, glowing in the air above us.

40Geomagnetic latitude aurora have reached in an extreme (G5) storm

1 September 1859 · 10 May 2024

The great storms

On 1 September 1859 the astronomer Richard Carrington was drawing sunspots. Two brilliant patches of light flared up and faded within minutes. The next day, aurora were seen farther from the poles than ever recorded. Telegraph wires carried currents strong enough to shock their operators.

NOAA calls it the largest geomagnetic storm on record. Carrington's notes helped link flares on the Sun with storms on Earth.

On 10 May 2024, NOAA observed G5 conditions for the first time since October 2003. Kp reached 9, the top of the scale. On NOAA's scale, a storm that strong can push the aurora as far as 40 degrees of geomagnetic latitude. Measured by its effect on Earth's magnetic field, the Carrington storm was still much stronger. Both reached us through the same shield we live inside tonight.