Guest post by David Archibald
Solar Cycle 24 is now over a year old, so it is appropriate to see how it is ramping up.
Solar Cycle 24 was a late starter, about three and a half years later than the average of the strong cycles in the late 20th century and almost three year later than the weak cycles of the late 19th century. It was almost as late as Solar Cycle 5, the first half of the Dalton Minimum. The last few months have seen it ramp up relatively rapidly.
[Note: Solar Cycle 22 and 23 are overlaid on solar cycle 3 and 4 above to show similarity]
Plotting up the last three solar cycles relative to the Dalton Minimum, another solar minimum is not precluded by the data to date.
With Solar Cycle 23 ending up at twelve and a half years long, applying Friis-Christenson and Lassen theory to the temperature record of Hanover, New Hampshire results in a two degree centigrade decline in the annual average temperature at this location over the expected twelve years of Solar Cycle 24, from December 2009 to late 2021. Given some record low monthly averages in the northeast US in the recent summer, and the current cold winter, this cooling is well under way.