Because of the inclination of the Moon's orbit, the Moon is above the horizon at the North and South Pole for almost two weeks every month, even though the sun is below the horizon for six months at a time. The period from moonrise to moonrise at the poles is quite close to the sidereal period, or 27.3 days. When the Sun is the furthest below the horizon (Winter Solstice), the Moon will be full when it is at its highest point.