Monthly Ri Report

:Issued: 2025 Nov 01 08:51 UTC
:Product: documentation at http://www.sidc.be/products/ri 
#-------------------------------------------------------------#
# MONTHLY TABLE OF THE INTERNATIONAL TOTAL SUNSPOT NUMBER     #
# AND 12-MONTH PREDICTIONS from the World Data Center SILSO   #
#-------------------------------------------------------------#

Provisional International monthly mean Sunspot Number for
October 2025 : 114.6 (one hundred and fourteen point six)

Maximum : 173 on 3 // Minimum : 44 on 31

Provisional daily International Sunspot Numbers for October 2025 : 

      1..167    6..146   11..106   16..134   21..122   26..103   31.. 44
      2..169    7..124   12..128   17..119   22..110   27.. 98
      3..173    8.. 77   13..128   18..114   23..100   28..114
      4..154    9.. 61   14..126   19..105   24..101   29..100
      5..148   10.. 79   15..122   20..110   25..100   30.. 70

61 cooperating stations on November 1, 09 UT

Predictions of the monthly smoothed Sunspot Number using the last
provisional value, calculated for April 2025 : 133.3 (+-5%)

            SM    CM                 SM    CM                 SM    CM     

2025 May   129   131     2025 Nov   111   121     2026 May   101   117
     Jun   124   130          Dec   109   121          Jun    99   113
     Jul   118   129     2026 Jan   108   121          Jul    97   110
     Aug   116   126          Feb   106   121          Aug    95   107
     Sep   114   123          Mar   105   120          Sep    93   104
     Oct   112   120          Apr   103   119          Oct    90   102

SM : SIDC classical method : based on an interpolation of Waldmeier's
standard curves; the estimated error ranges from 7% (first month) to
35% (last month)
CM : Combined method : the combined method is a regression technique
coupling a dynamo-based estimator with Waldmeier's idea of standard
curves, due to K. Denkmayr.
ref. : K. Denkmayr, P. Cugnon, 1997 : "About Sunspot Number Medium-Term
Predictions", in "Solar-Terrestrial Prediction Workshop V", eds.
G. Heckman et al., Hiraiso Solar Terrestrial Research Center, Japan, 103



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