Tides are the changes in water levels generated over large lakes and seas, and occur due to the interplay of gravitational forces between the moon and the sun on water
Spring tides are tides with the highest high tides and the lowest low tides. They occur when the moon is full and during a new moon. This is when the earth, moon, and sun are in line with one another, and the gravitational force exerted by the moon and the rotational force of the earth pulls the water on either side towards the sun and moon.
Neap tides, on the other hand, are tides where the high tides are lower than average and the low tides are higher than average. Such tides occur when the moon is at its first and third quarter, which is when the sun and moon are perpendicular to one another with respect to the earth; the gravitational forces on the water exerted by the sun and moon therefore act in different directions.
Our local tidal data is obtained from the Maritime and Port Authority of Singapore (MPA).