Sun · Solar Cycle
Sunspot Number Today and Solar Cycle Tracker
See today's sunspot count and the active region table on the Sun dashboard:
Open today's sunspot regions →What this means
Sunspots are cooler, darker patches on the photosphere where strong magnetic fields rise from the Sun's interior. A higher daily count means the Sun is more magnetically active and more likely to produce flares and coronal mass ejections.
The Sun cycles between quiet (solar minimum) and active (solar maximum) periods roughly every 11 years. We are currently near the peak of Solar Cycle 25.
How to read this data
A "region" is a single sunspot group with its own NOAA-assigned number. Each region has an area (millionths of the visible disk), a spot count, and a magnetic class — simple alpha groups are calm, while complex beta-gamma-delta groups are the ones most likely to flare.
The total daily sunspot number combines the number of groups and individual spots into one comparable index used by astronomers since the 1800s.
Why it matters
Sunspot activity is the best long-term proxy for how stormy near-Earth space will be. It drives flare frequency, aurora chances, satellite drag, and even small fluctuations in total solar irradiance reaching Earth.
Students and researchers use the daily sunspot number to track Solar Cycle 25 and compare it with cycles going back to 1755.
Active region data refreshes daily from NOAA SWPC.
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Created by Nicholas Tyo