  Is Solar Cycle 24 anomalous? How do we predict the main features of a
forthcoming cycle? In order to reply such questions, this work partitions
quantitatively each cycle into valley, ascend, peak, and descend phases,
statistically investigate the correlations between valley phase and the
forthcoming cycle. We find that the preceding valley phase may dominate and can
be predictor of the forthcoming cycle: (1) The growth rate in ascend phase
strongly negatively correlates to valley length and strongly positively
correlates to cycle maximum. (2) The cycle maximum strongly negatively
correlates to valley length, and strongly positively correlates to cycle
minimum. (3) The cycle period strongly negatively correlates to the valley
variation. Based on these correlations, we conclude that the solar cycle 24 is
a relatively weak and long cycle which is obviously weaker than Cycle 23. The
similarity analysis also presents the similar result. The Cycle 25 is also
inferred possibly to be a weak cycle. These results can help us understanding
the physical processes of solar cycles.
