Solar wind
speed: 457.0 km/sec
density: 2.4 protons/cm3
more data: ACE, SOLAR-1
Updated: Today at 1232 UT
X-ray Solar Flares
6-hr max: C3
0644 UT Oct18
24-hr: C3
0644 UT Oct18
explanation | more data
Updated: Today at: 1236 UT
Daily Sun: 18 Oct 26
Expand: labels | no labels
Sunspot 4551 has a 'beta-gamma' magnetic field that harbors energy for M-class solar flares. However, fast-growing sunspot 4556 is of greater interest. It has doubled in size since yesterday and has a complex morphology typical of flaring sunspots. Credit: NASA/SDO

Sunspot number: 87
What is the sunspot number?
Updated 18 Oct 2026
Current Auroral Oval:
Switch to: Europe, USA, New Zealand, Antarctica
Credit: NOAA/Ovation
Planetary K-index
Now: Kp= 1.67 quiet
24-hr max: Kp= 3.00
quiet
explanation | more data
Interplanetary Mag. Field
Btotal: 3.4 nT
Bz: 0.9 nT north
more data: ACE, DSCOVR
Updated: Today at 1233 UT
Coronal Holes: 18 Oct 26

Solar wind flowing from this southern coronal hole will reach Earth on Oct 20. .
Credit: NASA/SDO | more data

Spotless Days
Current Stretch: 0 days
2026 total: 4 days (2%)
2025 total: 0 days (0%)
2024 total: 0 days (0%)
2023 total: 0 days (0%)
2022 total: 1 day (<1%)
2021 total: 64 days (18%)
2020 total: 208 days (57%)
2019 total: 281 days (77%)
2018 total: 221 days (61%)
2017 total: 104 days (28%)
2016 total: 32 days (9%)
2015 total: 0 days (0%)
2014 total: 1 day (<1%)
2013 total: 0 days (0%)
2012 total: 0 days (0%)
2011 total: 2 days (<1%)
2010 total: 51 days (14%)
2009 total: 260 days (71%)
2008 total: 268 days (73%)
2007 total: 152 days (42%)
2006 total: 70 days (19%)

Updated 18 Oct 2026


Thermosphere Climate Index
today: 12.47
x1010 W Neutral
Max: 49.4
x1010 W Hot (10/1957)
Min: 2.05
x1010 W Cold (02/2009)
explanation | more data: gfx, txt
Updated 17 Oct 2026

The Radio Sun
10.7 cm flux: 131 sfu
explanation | more data
Updated 17 Oct 2026


SPACE WEATHER
NOAA Forecasts
Updated at: 2026 Oct 17 2200 UTC
FLARE
0-24 hr
24-48 hr
CLASS M
20 %
20 %
CLASS X
05 %
05 %
Geomagnetic Storms:
Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm
Updated at: 2026 Oct 17 2200 UTC
Mid-latitudes
0-24 hr
24-48 hr
ACTIVE
10 %
20 %
MINOR
05 %
05 %
SEVERE
01 %
01 %
High latitudes
0-24 hr
24-48 hr
ACTIVE
15 %
15 %
MINOR
15 %
20 %
SEVERE
15 %
25 %
 
Sunday, Oct. 18, 2026
What's up in space
       
 

AI writing is everywhere -- except here. This website is written by Dr. Tony Phillips, a carbon-based lifeform with 30 yrs of forecasting experience. Our guarantee: If you find a mistake, it was made by a real human being.

 

GEOMAGNETIC STORM WATCH (G1): A solar wind stream is approaching Earth. ETA: Oct. 20th. NOAA forecasters say that G1-class geomagnetic storms and high-latitude auroras are possible when it arrives. Aurora alerts: SMS Text.

THE SUN'S ELUSIVE COUNTERGLOW: It has been called "the skygazer's holy grail." In fact, most have never heard of it: Gegenshein is a faint patch of light in the night sky directly opposite the sun. Fins Eirexas photographed it on Oct. 15th from Mazaricos, Spain:

"This is the Gegenschein imaged above the dolmen of Gándara de Baiñas, from the Fervenza reservoir," says Eirexas. "A rare occasion to see two elusive targets: the fuzzy Gegenschein struggling with light pollution and this megalithic monument, emerged from the water due to the current draught."

Gegenschein is German for"counter-shine." It’s sunlight bouncing off dust in the plane of the solar system. At the antisolar point, each grain is fully lit, like a tiny full Moon, so it reflects sunlight straight back toward Earth.

The glow is several times wider than the full Moon and so dim that city lights wipe it out. To see it you need a dark, moonless sky around midnight, when the gegenschein sits highest. A dolmen pointing the way helps, too.

Realtime Space Weather Photo Gallery
Free:
Space Weather Newsletter

THE HALLOWEEN FIREBALLS ARE COMING: We love our new Backyard Astronomy Alert Service, and now is a good time to try it out. Earth is entering the Taurid debris stream--source of the annual Halloween fireballs. For the next 3 to 4 weeks, Earth will surf through a complex meteoroid field producing bright meteors often seen while trick-or-treating.

Subscribers to our service receive instant text messages when anything is happening in the sky--meteor outbursts, space station flybys, bright auroras and much more. Companion emails contain sky maps and observing tips--everything you need to fully experience the event. It also makes a great gift!

Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education


Realtime Aurora Photo Gallery
Free:
Spaceweather.com Newsletter

  All Sky Fireball Network
Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.

On October 16, 2026, the network reported 20 fireballs.
(13 sporadics, 3 Southern Taurids, 2 epsilon Geminids, 1 October Ursae Majorids, 1 Orionids)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

  Near Earth Asteroids
Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.
On October 18, 2026 there were 2349 potentially hazardous asteroids.
Recent & Upcoming Earth-asteroid encounters:
Asteroid
Date(UT)
Miss Distance
Velocity (km/s)
Diameter (m)
2026 TL77
2026-Oct-12
5.4 LD
14.9
63
2026 TC6
2026-Oct-12
9.8 LD
10.3
22
2026 TX3
2026-Oct-12
18.9 LD
8.7
27
2026 TN77
2026-Oct-12
0.1 LD
15.3
13
2026 TF59
2026-Oct-12
1 LD
7
6
2026 TV3
2026-Oct-12
9.2 LD
9
21
2026 TQ8
2026-Oct-12
11 LD
23
42
2026 TS3
2026-Oct-12
12.1 LD
9.4
29
2026 TC1
2026-Oct-13
16.1 LD
13.2
31
2026 TJ
2026-Oct-13
19.7 LD
7.3
117
2026 TK35
2026-Oct-13
19.2 LD
12.9
71
2026 TR8
2026-Oct-13
8.9 LD
9.1
18
2026 TG6
2026-Oct-13
12.6 LD
15.4
29
2026 TM35
2026-Oct-13
3.9 LD
10.2
11
2026 TG9
2026-Oct-14
0.6 LD
11.7
12
2026 TO69
2026-Oct-14
4.5 LD
12.1
21
2026 TP6
2026-Oct-15
0.6 LD
10.3
13
2026 UA
2026-Oct-15
3.5 LD
16.8
16
2026 TF4
2026-Oct-15
7.1 LD
4.9
11
2026 UG
2026-Oct-15
5 LD
8.5
12
2022 UP6
2026-Oct-15
2.6 LD
9
8
2026 UB
2026-Oct-15
6.5 LD
16.3
20
2000 SZ162
2026-Oct-16
19.9 LD
5.7
12
2026 TE2
2026-Oct-16
6 LD
14.7
25
2026 TB2
2026-Oct-16
5 LD
8.8
32
2026 TA94
2026-Oct-16
5.4 LD
7.4
13
2026 TC94
2026-Oct-18
6.6 LD
10.5
15
2026 TS
2026-Oct-18
2.4 LD
10.3
55
2026 UF
2026-Oct-18
6.8 LD
7.6
34
2026 TN67
2026-Oct-18
16.6 LD
6.9
28
2026 TD2
2026-Oct-20
7.3 LD
12.3
44
2026 TP
2026-Oct-20
12.1 LD
9.9
51
2020 FN3
2026-Oct-20
12.4 LD
5.8
45
2026 TM67
2026-Oct-20
11.7 LD
14.3
55
2026 TV8
2026-Oct-21
4.8 LD
9.2
26
2026 TU1
2026-Oct-22
12.8 LD
7.9
25
2026 TX84
2026-Oct-22
10.6 LD
7.4
23
2026 TK77
2026-Oct-22
9.7 LD
6.2
15
2017 UX7
2026-Oct-22
17 LD
10.3
27
2026 TV86
2026-Oct-23
5.6 LD
5.7
18
2026 TR35
2026-Oct-23
15 LD
21
52
2026 TT3
2026-Oct-24
12.8 LD
12.8
46
2026 UE
2026-Oct-25
5.3 LD
15.8
24
2026 TB8
2026-Oct-25
7.1 LD
7.8
59
2026 TB94
2026-Oct-27
5.1 LD
11.6
27
2018 GS1
2026-Oct-28
11.1 LD
9.3
108
2022 UV21
2026-Oct-29
14.8 LD
9.6
13
2026 UD
2026-Oct-30
11.5 LD
7.8
28
2025 UK9
2026-Oct-31
0.8 LD
7.8
4
524522
2026-Nov-02
15.7 LD
8.7
277
2021 VC4
2026-Nov-03
6 LD
11.2
15
2017 WJ2
2026-Nov-05
15.6 LD
11.8
118
2016 VZ1
2026-Nov-05
20 LD
13.5
21
2001 KF54
2026-Nov-06
18.9 LD
16.4
391
2025 UF5
2026-Nov-09
18.9 LD
1.9
10
2015 VH65
2026-Nov-10
9.7 LD
8
10
2012 YD7
2026-Nov-10
18.6 LD
7.5
49
2023 VF3
2026-Nov-11
8.5 LD
8.8
19
2022 MP2
2026-Nov-13
19.8 LD
3.8
23
2025 VG5
2026-Nov-13
18.2 LD
4.9
16
2023 VE6
2026-Nov-17
18.4 LD
10.1
13
2019 WT1
2026-Nov-18
19.7 LD
9.7
16
2018 NE1
2026-Nov-19
16.7 LD
13.3
74
2026 TB84
2026-Nov-20
12.2 LD
9.8
67
2025 CP1
2026-Nov-30
12.9 LD
10.8
6
2019 XF2
2026-Dec-04
3.1 LD
10.2
14
2023 XH3
2026-Dec-06
18.7 LD
16.5
14
2020 XC3
2026-Dec-08
14.5 LD
14.3
110
2016 NV
2026-Dec-08
14.3 LD
10.4
379
2010 VQ
2026-Dec-12
4.6 LD
4.3
10
2025 XN6
2026-Dec-12
6.9 LD
12.2
5
2026 LZ1
2026-Dec-14
14.4 LD
11.2
36
Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU.
  Cosmic Rays in the Atmosphere

SPACE WEATHER BALLOON DATA: Almost once a week, Spaceweather.com and the students of Earth to Sky Calculus fly space weather balloons to the stratosphere over California. These balloons are equipped with sensors that detect secondary cosmic rays, a form of radiation from space that can penetrate all the way down to Earth's surface. Our monitoring program has been underway without interruption for 10 years, resulting in a unique dataset of in situ atmospheric measurements.

Latest results (Nov. 2024): Atmospheric radiation is sharply decreasing in 2024. Our latest measurements in November registered a 10-year low:

What's going on? Ironically, the radiation drop is caused by increasing solar activity. Solar Cycle 25 has roared to life faster than forecasters expected. The sun's strengthening and increasingly tangled magnetic field repels cosmic rays from deep space. In addition, solar coronal mass ejections (CMEs) sweep aside cosmic rays, causing sharp reductions called "Forbush Decreases." The two effects blend together to bring daily radiation levels down.

.Who cares? Cosmic rays are a surprisingly "down to Earth" form of space weather. They can alter the chemistry of the atmosphere, trigger lightning, and penetrate commercial airplanes. According to a study from the Harvard T.H. Chan school of public health, crews of aircraft have higher rates of cancer than the general population. The researchers listed cosmic rays, irregular sleep habits, and chemical contaminants as leading risk factors. A number of controversial studies (#1, #2, #3, #4) go even further, linking cosmic rays with cardiac arrhythmias and sudden cardiac death.

Technical notes: The radiation sensors onboard our helium balloons detect X-rays and gamma-rays in the energy range 10 keV to 20 MeV. These energies span the range of medical X-ray machines and airport security scanners.

Data points in the graph labeled "Stratospheric Radiation" correspond to the peak of the Regener-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth's atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Regener and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.

  Essential web links
NOAA Space Weather Prediction Center
  The official U.S. government space weather bureau
Atmospheric Optics
  The first place to look for information about sundogs, pillars, rainbows and related phenomena.
Solar Dynamics Observatory
  Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever.
STEREO
  3D views of the sun from NASA's Solar and Terrestrial Relations Observatory
Solar and Heliospheric Observatory
  Realtime and archival images of the Sun from SOHO.
SolarMonitor.org
  information about sunspots based on the latest NOAA/USAF Active Region Summary
Starlink Satellite Statistics
  current counts of failed and deployed Starlink satellites from Jonathan's Space Page. See also, all satellite statistics.
The Aerospace Corporation
  Authoritative predictions of space junk and satellite re-entries
Daily Sunspot Summaries
  from the NOAA Space Environment Center
NOAA 27-Day Space Weather Forecasts
  fun to read, but should be taken with a grain of salt! Forecasts looking ahead more than a few days are often wrong.
Aurora 30 min forecast
  from the NOAA Space Environment Center
Live Aurora Webcam
  from Lights over Lapland
Heliophysics
  the underlying science of space weather

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SATELLITE DRAG
today: 52.5 m/day ↑ JanOct 2026 max: 127.6 (Jan 20)
2026 min: 19.7 (Aug 10)

Explanation: This is how fast a typical Starlink at 480 km is sinking due to aerodynamic drag: more information.
Updated: 17 Oct 2026

Starlink Statistics
Total Launched: 13,075
In orbit:
11,154
Updated: 17 Oct 2026

Starlink Re-entries (2026)
January: 24
February: 54
March: 48
April: 51
May: 60
June: 35
July: 52
August: 32
September: 47
October: 29
Updated: 17 Oct 2026

Starlink Re-entries (yearly)
2020 total: 46
2021 total: 78
2022 total: 100
2023 total: 88
2024 total: 308
2025 total: 657
2026 total: 421 so far

Updated: 17 Oct 2026


Data sources: #1, #2, #3; Histograms: launches, reentries






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