The basic lunar cycle of a body of water consists of two high tides and two low tides, which occur every 24 hours and 50 minutes. The basic cycle of solar tides is 24 hours.
Tides rely on the position of the sun and moon relative to the earth, which means that the strength and length of the tides can vary. For example, when the three are nearly in a straight line, the sun's gravitational pull is added to that of the moon's, which produces higher high tides and lower low tides. These tides occur during the new moon and full moon.