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Sunspot Number History & HF Propagation

Daily sunspot numbers provide a longer view of solar activity. Compare the last month, quarter or year, then combine the trend with current solar flux and geomagnetic conditions when planning HF operation.

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NOAA observed readings

Daily Sunspot Number

Latest reading: 96 on November 7, 2026.

96 on Nov 7, 2026

0316394125Oct 9, 2026Nov 7, 2026
Daily reading 30-day average
View daily values as a table
DateSunspot number
Nov 7, 202696
Nov 6, 202691
Nov 5, 202689
Nov 4, 202664
Nov 3, 202641
Nov 2, 202637
Nov 1, 202630
Oct 31, 202624
Oct 30, 202636
Oct 29, 202622
Oct 28, 202612
Oct 27, 202625
Oct 26, 202625
Oct 25, 202622
Oct 24, 202625
Oct 23, 202651
Oct 22, 202649
Oct 21, 202666
Oct 20, 202666
Oct 19, 202666
Oct 18, 202682
Oct 17, 202687
Oct 16, 202681
Oct 15, 2026104
Oct 14, 2026124
Oct 13, 2026102
Oct 12, 202693
Oct 11, 202694
Oct 10, 202699
Oct 9, 202693

Daily readings: NOAA Space Weather Prediction Center. A missing date is left blank, not treated as zero. The optional average is calculated from 30 consecutive daily readings.

What does this number mean?

The sunspot number is an activity index based on the number of sunspot groups and individual spots visible on the Sun. It is not simply a count of spots. NOAA publishes the daily observed value shown here.

Why does it matter for HF?

Over weeks and months, higher sunspot activity is often associated with stronger ionization high in Earth's atmosphere. That can help higher HF bands, especially 15, 12, and 10 meters, support longer-distance contacts.

How should I use the graph?

Look for the direction of the trend, not a promise about a particular day or path. Today's openings also depend on solar flux, geomagnetic conditions, flares, daylight, season, and the stations at both ends of a contact.

Learn more from NOAA's solar cycle explanation and ARRL's HF propagation guide.

Build a clearer picture

Explore solar & geomagnetic conditions

Each measurement tells part of the story. Compare solar activity with geomagnetic conditions, daylight and your operating path.

Live HF Propagation & Space Weather

Check current HF radio conditions with NOAA solar flux, Kp, solar wind, Bz, X-ray and sunspot data, history charts, band guidance and a live greyline map.

Explore current conditions →

Solar Flux Index (SFI) & F10.7 History

Track NOAA's Solar Flux Index with 7, 14 and 30-day F10.7 charts, daily readings and a 7-day average. Learn what solar flux means for HF propagation.

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Planetary Kp Index & Geomagnetic Activity

Explore NOAA planetary Kp index history over 1, 3 or 7 days. Compare three-hour geomagnetic readings and learn how disturbed conditions can affect HF radio.

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Solar Wind Speed & HF Radio Conditions

Follow NOAA solar wind speed in km/s with 6, 12 and 24-hour history charts. Learn why sustained speed changes, IMF Bz and Kp matter together for HF radio.

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IMF Bz & the Solar Wind Magnetic Field

View NOAA IMF Bz history over 6, 12 or 24 hours. Understand positive and negative nanotesla readings and why sustained southward Bz matters for geomagnetic activity.

Explore the readings →

GOES X-Ray Flux & Solar Flare History

Explore NOAA GOES X-ray flux and solar flare history over 1, 3 or 7 days. Understand A, B, C, M and X classes and their relevance to sunlit-side HF radio blackouts.

Explore the readings →