  The dynamic activity of the Sun -- sustained by a magnetohydrodynamic dynamo
mechanism working in its interior -- modulates the electromagnetic, particulate
and radiative environment in space. While solar activity variations on short
timescale create space weather, slow long-term modulation forms the basis of
space climate. Space weather impacts diverse space-reliant technologies while
space climate influences planetary atmospheres and climate. Having prior
knowledge of the Sun's activity is important in these contexts. However,
forecasting solar-stellar magnetic activity has remained an outstanding
challenge. In this review, predictions for sunspot cycle 24 and the upcoming
cycle 25 are summarized, and critically assessed. The analysis demonstrates
that while predictions based on diverse techniques disagree across solar cycles
24--25, physics-based predictions for solar cycle 25 have converged and
indicates a weak sunspot cycle 25. It is argued that this convergence in
physics-based predictions is indicative of progress in the fundamental
understanding of solar cycle predictability. Based on this understanding,
resolutions to several outstanding questions related to solar cycle predictions
are discussed.
