Educational
FORECAST SOL: Normal green MAG: Normal green ION: Normal green Looking for something? Site search go to search page
HomeEducationalThe Sun and Solar ActivitySolar CycleLarge Monthly Sunspot Numbers Thursday, Mar 05 2015 04:06 UT
The Sun and Solar Activity

Large Monthly Sunspot Numbers

The following table ranks, in order, the 20 single months from solar cycle 18 to present for which the sunspot number was at its highest monthly-averaged value.

Ranking Month Solar Cycle Sunspot Number
1October 195719253.8
2December 195719239.4
3September 195719235.8
4January 195919217.4
5November 195719210.9
6January 195819202.5
7November 195619201.3
7May 194718201.3
9September 195819201.2
10June 195719200.7
12August 199022200.3
11August 195819200.2
13August 195919199.6
14June 198922196.2
14April 195819196.0
16December 195619192.1
17July 195819191.4
18March 195819190.7
19April 194818189.7
20August 194718188.8

Notes

  1. The strength of the record Solar Cycle 19 (April 1954 to October 1964) is indicated by the fact that it provides a total of 15 entries out of the list of 20. Also, that cycle contributes all of the top seven months in the list.
  2. Even though Cycle 18 (February 1944 to April 1954) was relatively weaker than Cycle 21 (June 1976 to September 1986) and Cycle 22 (September 1986 to May 1996), it contributes three entries to the list.
  3. Cycle 22 contributes two entries to the list.
  4. Cycles 20 (October 1964 to June 1976), 21, 23 (May 1996 to December 2008) and 24 (December 2008 to present) do not contribute to the list.

Material prepared by Richard Thompson

go to top of page