Assessing the Evolution of Solar Cycle 25: A Weak-moderate Cycle

Abstract

This note aims to analyze the evolution of the sunspot number for Solar Cycle 25, updating our previous findings on this topic. We compare daily, monthly and 13 months smoothed sunspot numbers for Solar Cycle 25 with those from previous cycles since mid-18th century (Solar Cycles 1–25). The highest daily, monthly and 13 months smoothed values for Solar Cycle 25 are significantly lower than the mean and median values considering all cycles. In particular, Solar Cycle 25 ranks 17th in terms of the highest 13 months smoothed sunspot number at this point in the cycle. Based on current data and the progression toward its maximum, we conclude that Solar Cycle 25 is likely to be a weak to moderate cycle, consistent with our earlier analyses. In addition, we find that Solar Cycles 13, 14, and 16 have the most similar behavior to that of Solar Cycle 25. Assuming a cycle length for Solar Cycle 25 similar to those of the above cycles, we estimate that the minimum of Solar Cycle 26 will be in 2030–2031.