Variability of the Sun will be discussed. Differential rotational rate of the magnetic field and its temporal dependence has been evidenced at different latitudes through activity cycles.The velocity of the meridional flows of the magnetic field was estimated.

Observations of the large scale magnetic field in the photosphere taken at the Wilcox Solar Observatory since 1976 up to 2007 have been analyzed to deduce its latitudinal and longitudinal structures and asymmetry, its differential rotation, and their variability in time.

The latitudinal topology of the photospheric magnetic field is composed of
1) a four zonal 20-22-year periodical structure and
2) polarity's waves running from the equator to the poles with periods of 2-3-years about.

North-South asymmetry of solar magnetic field and its short and long term variability in time have been studied.

Extremely interesting quasi-stable over 30 years longitudinal structure has been found.

These results are fundamental for the understanding of the magnetic origin of the solar activity, dynamics, heliospheric structure and for the prediction of the solar wind and magnetospheric perturbations.