NOAA SWPC · updated continuously

Band Conditions

The solar and geomagnetic numbers that decide which HF bands are usable, and what they imply. Free, public data from the NOAA Space Weather Prediction Center.

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Good Fair Poor

Band	Day	Night

This is a rule of thumb, not a forecast

These ratings are derived from solar flux and the K index alone. Real propagation depends on the path, your antenna and the hour. For ground truth, transmit one FT8 cycle and look at PSK Reporter, or check a live MUF map at prop.kc2g.com. Reading Propagation explains what each of these numbers actually does.

Data from the NOAA Space Weather Prediction Center, a public service with no API key, read through a server-side proxy and cached so the site is not polling a government endpoint on every visit.

Band Conditions

NOAA space weather scales

What should be open