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Solar Indices Bulletin

Published by NOAA National Centers for Environmental Information | National Oceanic and Atmospheric Administration, Department of Commerce | Metadata Last Checked: December 19, 2025 | Last Modified: 2014-08-10T00:00:00.000+00:00
Solar Indices Bulletin is a prompt monthly information product that is distributed within two weeks after the observation month closes. For the month just ended, this 2-page circular tabulates daily values of sunspot numbers and 10.7 cm solar radio flux observed at Penticton (previously at Ottawa); flux measurements at eight other wavelengths are included. Page 2 of the Bulletin gives a table of smoothed monthly mean sunspot numbers for the current solar cycle--a table that begins with smoothed observed values for each month and ends with predictions.

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