From the March 14 edition of the ARRL Letter:
According to NASA, the current solar cycle — Solar Cycle 24 — should hit its “solar max” sometime in this year, but so far, solar activity has been relatively low. According to an article by NASA’s Dr Tony Phillips, this period of quiet has led some observers to wonder if forecasters missed the mark. But solar physicist Dean Pesnell of NASA’s Goddard Space Flight Center has a different explanation: “This is solar maximum. But it looks different from what we expected because it is double peaked.” Pesnell noted similarities between the current cycle and Solar Cycle 14, which happened between February 1902 and August 1913 and experienced a double peak. If the two cycles are in fact twins, he said that “it would mean one peak in late 2013 and another in 2015. Read more here.