Yesterday was a sunspot-free day on the visible solar disk. It is not unusual for the Sun to be spot-free and
it will become more common as the Sun gets closer to solar minimum. Check out the Solar Cycle 24 XPOW.
Place the mouse over the image to see what the sun looks like in X-Rays. You'll notice that there are still regions on the disk where the Sun is very bright in X-rays.
These regions are still sources of solar activity. So sunspot-free days don't necessarily mean solar activity-free days.
Keywords: Full Disk, Synoptic