  The Sun's polar magnetic fields change their polarity near the maximum of
sunspot activity. We analyzed the polarity reversal epochs in Solar Cycles 21
to 24. There was a triple reversal in the N-hemisphere in Solar Cycle 24 and
single reversals in the rest of cases. Epochs of the polarity reversal from
measurements of the Wilcox Solar Observatory (WSO) are compared with ones when
the reversals were completed in the N- and S-hemispheres. The reversal times
were compared with hemispherical sunspot activity and with the Heliospheric
Current Sheet (HCS) tilts, too. It was found that reversals occurred at the
epoch of the sunspot activity maximum in Cycles 21 and 23, and after the
corresponding maxima in Cycles 22 and 24, and one-two years after maximal HCS
tilts calculated in WSO. Reversals in Solar Cycles 21, 22, 23, and 24 were
completed first in the N-hemisphere and then in the S-hemisphere after 0.6,
1.1, 0.7, and 0.9 years, respectively. The polarity inversion in the near-polar
latitude range \pm(55-90)^\circ occurred from 0.5 to 2.0 years earlier that the
times when the reversals were completed in corresponding hemisphere. Using the
maximal smoothed WSO polar field as precursor we estimated that amplitude of
Solar Cycle 25 will reach 116 \pm 12 in values of smoothed monthly sunspot
numbers and will be comparable with the current cycle amplitude equaled to
116.4.
