Helevos only has two fairly small moons, so daily lunar tides are only very slight and essentially insignificant. However, they are highest every 1.3 years, when the planet comes into conjunction with the gas-giant Kwato'or.

During this period, for several weeks the action of the giant planet and the sun creates unusually high tides. These tides often combine with storms to wreak havoc on coastlines. Tides of up to 3 metres create massive tidal waves. which, aided by the planet's slightly less than Earth-standard gravity, have been known to cause massive flooding far inland.

Many coastal and sea-faring peoples have based their religions and calendars on this regular inundation.